11683 Cavity Product Guide v21:Layout 1 DPC Brochure.pdf · Product Guide is tabbed in its own...

damp-proofing & membranesPRODUCT GUIDEvolume 21

‘Benefit product performance protection.

The only tray manufacturer awardedEuropean Technical Approval.

You cannot purchase a higher standard.’

Cl/SfB (21.9) Xn6 (L34)

Reminder...

new product guide

release date

winter 2010

ETA 03/0014Cavitrays

PerformRIBA Product Selector Type N Sitesealer Certificate No.1172

Members of the Radon Council.

Confirmed Cavitrays meettechnical requirements

Cavity Trays LimitedYeovil Somerset BA22 8HU

telephone 01935 474769

fax 01935 428223

email [email protected]

web www.cavitytrays.com

help desk 0800 7311779 (freephone)

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Product Guidesections index

The purpose of this manual is

to provide details of products

and systems and draw to your

attention design

considerations plus cost

implications. Having evaluated

and made your selections,

there remains a possibility that

an alternative might be

suggested for substitution at a

later date on the pretext that it

is equal and approved. How

can you be sure? To preserve

the quality of your original

decision, we operate an

appraisal programme.

Comparisons are made

embracing costs, materials,

performance, advantages,

ease of installation, NHBC,

Zurich Insurances and British

Standards compliance,

warranties, and product

liability. We know we offer

products that promote the

long term integrity of the

structure. In the interests of

your own personal liability and

to secure products and

materials with a proven track

record and warranty, please

contact us if an alternative is

ever suggested. At Cavity

Trays of Yeovil, we realise your

objectives and will work

with you.

better for architect, builder,client and peace of mind...

Our conditions of supply apply in all instances. A copy of the company’s terms and conditions is available upon request. Cavity Trays ltd shall not be liable for any consequential loss whether this arises from a breach of duty incontract or any other way. Quoted despatch dates and carriage methods apply to the anticipated date of despatch and the anticipated mode of carriage only and speed shall not form any part of any contract. As part of ourcontinuous product development, we reserve the right to amend or change specifications without notice.

Further Services

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product codes -your optionWe purposely use product

names in full and also make

use of the first characters of

such names to identify our

products.

designed for youMuch of our work involves

the design and manufacture

of non-standard and special

requirements. Our proven and

innovative approach to

problem solving offers speedy

and cost-effective answers.

We are pleased to submit

schedules, function drawings

and recommendations

without charge.

You may draw on our

experience and know-how,

which cannot be matched by

any other organisation in our

specialised field.

alternative materialsPreformed cavitrays and

flashings can be manufactured

in alternative materials for

specialist applications.

help deskOur Help Desk is available

by fax, email and telephone.

If in any doubt please

contact us. There is no

charge for this service.

area technicaladvisersOur trained Technical

Managers are located

throughout the United

Kingdom. If you wish to

receive a visit to discuss your

particular project or

requirements, please contact

our Administration Centre.

help on siteTechnical Managers are

pleased to visit sites for the

purpose of instructing

operatives how the products

should be installed.

guaranteeOur approved products are

accompanied with product

performance liability

protection for the benefit of

architect, builder and client.

seminarsWe are pleased to arrange

seminars and application

briefings, on your premises

or in your geographic area.

Please write to our Seminar

Booking Clerk at our

Administration Centre.

specifying by name -warningPlease specify our company

name, address and product

in full. This will ensure that

you will receive the items you

require with all the benefits

and warranties that support

our approved cavitray

systems and Agreement

certified products. Beware

4

si momentumrequires circumspiceif you need encouragement, look around you

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imitations. Having selected

our products, it is in your

interest to ensure only the

selected approved products

are used. This is possible by

clearly specifying.

the local government act1999 - best valueBest Value embraces

achieving the maximum

value for money by supplying

efficient and reliable quality

goods and services.

importantOn every product page we list

a number of technical

observations and

considerations appropriate to

the product. Please refer to

these comments when

making comparisons with

other systems. This will

ensure an appreciation of the

major technical aspects and

requirements. Comparison

will also determine whether

other systems offer the same

level of protection, integral

features and reliability. In

many instances we consider

the technical aspects listed

essential.

The implications of the Latent

Damage Act and Consumer

Protection Act introduce

further demands for the

architect and contractor to

construct to a satisfactory

standard in the long term as

well as the short. Within the

recommended wording for

contract documentation, we

refer to a liability and

conformity document which

is available from this company.

Therefore, having established

that all the correct products

have been delivered to site, our

documentation procedure then

commences.

Following correct installation and

completion in full of transactions

including financial settlement

within terms, a liability/

conformity document is issued.

We recommend this document

is attached to the contract

paperwork and subsequently

handed to the client. It is

assurance of protection for the

future. Our conditions of sale

apply at all times.

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a posteriorireasoning and knowledge

derived from experience

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Unusual Trays?

The yellow indicator advises the range of cavity widths for

which a product in standardformat is suitable. Forexample the Type X cavitrayhas an adjustable back thatwill service a cavity widthrange from 50mm up to200mm. Thus the yellow indicatorflags that product’s specificcavity range as 50 –200mm.

The green indicator advises when the product is available

in alternative bed widths andheights. For instance, if theexternal skin is of an unusualthickness it indicates a tray isavailable to accommodate thethickness encountered. Thisincludes compositeapplications such as masonrybuilt against a backing block.Similarly, we automaticallyensure any accompanyingvertical variation is taken intoaccount.

The blue indicator advises bespoke versions of the

product can be manufactured.Bespoke versions are basedon the design principles of thestandard product. For instanceit might be a circular cavitrayfor a round window that is solarge it is outside thestandard model range ofsizes. The blue BS bespokeindicator means there is asolution to your non-standardrequirement.

The red indicator advises the Cavi rating, which is the

fire integrity period. Thispredominately applies toclosers when tested to therequirements of the relevantquoted British Standard. ThusCavi 60 signifies 60 minutesfire integrity. The highest leveloffered is Cavi 240 providing4 hours integrity. The redindicator provides instantidentification.

non-standardtrays? we can supply

Cavity Trays of Yeovilbetter for architect, builder, client - and peace of mind

Our standard ranges of products are described within this manual.However, we appreciate the growing demand for solutions for theout of the ordinary applications one encounters in the constructionindustry. We are pleased to advise we can normally provide theanswer with products from our tailor-made and bespoke productfactory. A number of indicators to provide easy guidance:

Please refer to the indicators for quick and easy reference andselection. They are positioned at the bottom of the page, asshown in the example marked 1 opposite.

Why select Cavity Traysof Yeovil?Your project will be protected. Your

clients will benefit. We are the only

tray manufacturer awarded

European Technical Approval. You

cannot purchase a higher standard

to protect your building. We are also

the longest established specialists.

Does this best standardcost more?Using Cavity Trays of Yeovil

approved products generally cost no

more than alternatives. Plus we can

usually demonstrate overall savings

in your total expenditure.

Will I benefit in anyother way?By using approved cavitrays you can

eliminate your exposure to remedial

and corrective work. Your build

programme need not be hindered or

interrupted.

An assured approved standard of

detail protects your project.

Best standard - bestcost - is there anythingelse?Yes - peace of mind. Cavity Trays of

Yeovil approved cavitrays are

accompanied with a cavitray

performance liability protection

warranty.

It covers twenty years and is not

offered by any other manufacturer.

How do I know what Ineed?Available to you is our free take-off

and appraisal service. We provide

the product schedule. Alternatively

you may do this yourself if you prefer.

What happens if thereare no standardproducts to suit myscheme?We identify, design and advise you,

as part of our free service. We

operate the largest factory making

purpose-made trays and flashings.

You will be surprised how little

bespoke products need cost.

Can Cavity Trays ofYeovil visit?We will be delighted to visit you at

your site or office. Technical

Surveyors operate throughout the

United Kingdom. We advise on any

size of project or specific problem.

We will come to you.

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The Product Guide explained

phone01935 474769

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quick referencesymbolsThese symbols offer an ‘at a glance’ guide to eachproduct’s capabilities.

colour coded tabbingEach section of theProduct Guide is tabbed in its own colour for easeof use.

further informationcolumnA column featuring usefulinformation can be foundon most pages. Thisincludes designers’comments and technicalobservations.

product summaryThis is a brief list of theproduct’s benefits.

colour illustrationsThere are full colourillustrations throughout,helping to make it simpleto choose the rightproduct.

technical drawingsMany pages show linedrawings to demonstratehow the product may be used.

contact detailsOur order-line number and email can be found at theoutward facing side ofeach page - no need tolose your page whenmaking an enquiry.

we have added new features to aid identification and selection

1

1

2

3

3

4

4

5

5

6

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7

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Log onto www.cavitytrays.com to access the latest product information. Data sheets, productspecifications, CAD downloads and video demonstrations showing how products are used.

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Page 10Type B Provides vertical DPC element to existing cavity wall where skinchanges from exterior to interior status.

Moulded DPC barrier only for arches, thus permitting traditionalconstruction.

Vertical DPCCavitray

Page 11Type BA Cavity BarrierArch

A range of preformed, ready-shaped DPC cavitrays for use withproprietary metal lintels.

Page 12Type C Cavitray for use withlintels over openings

Preformed moulded cavicloaks for use within cavity walls.Cavicloaks are shaped to fit the construction detail intended.

Page 15Cavicloak Preformed dampcourses

Protection of masonry feature without dependence of support fromexternal skin.

Page 17CD Dropcloak Drop Cavicloak

Load bearing lintel to provide support over openings, withintegral shutter facility.

Page 18Cavilintel Lintel with integralsecurity shutter

Pre-shaped damp courses for use with system building.

To damp-proof an original outside wall which has become aninside wall by virtue of an extension being built.

Corrugated flashing suitable for use with plastic roof sheets only.

Page 21

Page 22

Page 25

DPC Profiles

Type E

Type F

SIPS panel DPC profilestimber frame profiles

General purpose DPC suitable for horizontal and verticaldamp-proofing of cavity walls.

Caviroll Premium DPC

Cavitray for insertioninto existing walls

Flashing for use with PVCcorrugated sheeting

To secure flashing in position and ensure correct linking withconventional DPC.

Page 26Type FAS Flashing anchoring andDPC integrity system

Provides reliable DPC system for general-purpose applicationsincluding changes of level, diaphragm walls and garage roofs.

Provides DPC support and closes cavity under parapet copings.Provides means of closing cavity in open eaves.

Cavitray damp course for circular openings.

For use at the ends of most popular DPC steel lintels. Theyprovide perfect ends, preventing discharge of water into cavity.

Pre-cut and preformed to suit a variety of applications.

Preformed cavitray for use over standard meter boxes(gas or electricity).

To weatherproof parapet walls.

Page 27

Page 29

Page 30

Page 31

Page 32

Page 35

Page 36

Type G

Type J

Type K

Type L

Lead Fab.

Type M

Type P

Cavitray DPC system

DPC Support andCloser

DPC cavitray for circularbullseye windows

Lintel Stopends

Lead Fabrications andlead supply services

Cavitray for use overmeter boxes

Cavitray for parapetwalls

SECTION ONEdamp-proof products

Page 20

Isolates threshold masonry and permits interfacing of flooringand reveal construction.

Page 33Type LTT Level threshold tray(threshold isolation DPC)

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Page 39

Page 40

Type R

Rain ScreenBaffles

Flashings and water baffle checks for stand-off rain screens.

To protect against damp and water penetration around sillsand thresholds.

Page 41Type TST Threshold and silloverlay tray

For use under brick or tile sills, providing a DPC andintegral guide for sill formation.

Page 42Type U Cavitrayfor undersills

Hidden appearance discreet weep glass-clear finish. Page 45Beak Weep Perp weep

To weep via a perp joint, thus promoting water evacuation fromDPC, lintel or cavitray whilst permitting the cavity to breathe.

Page 46Small Weep Hidden appearanceweepvent

Cavity wall weep, designed to provide an outlet drain todischarge water from tray/DPC.

Page 47Type W Cavitray weepvent

The purpose and function of the perp weep/ventilator isdescribed on the Type W page.

Preformed cavitray with integral lead flashing, forms steppedcavity DPC and flashing at the abutment of a pitched roof.

Multicourse cavitrays are proportioned to accept a variety ofwalling materials and dimensions.

Page 48

Page 49

Page 53

Euroweep

Type X

Multicourse

Alternative perp/weepventilator

Cavitray for gableabutments

Type X for gable abutmentmulticourse applications

Synthetic flashing substitute with no theft value. Page 54Perform Perform syntheticflashing

Preformed cavitrays for use within curved masonry, cylindricaltowers, round structures.

Preformed cavitrays for use with mullion window surroundsand similar.

Preformed fixing aid for use with polymer, bitumen and polytheneroll DPC.

Preformed Cavitrays compatible for use with masonry supportsystems and framed structures.

Page 56

Page 58

Page 59

Page 60

Curved

Type Y

Type Z

MasonrySupport

Curved cavitray, on plan concave and convex

Stone mullionassembly cavitrays

Cavistrap to fix andsupport flexible DPC

DPC for masonrysupport systems

Integral shuttering tray water-check former. Also suitable for closing cavities.

Cavitray cavity closer/water-check tray

Arresting planes

Product type codes within each section are listed in alphabetical order. In some instances, products are then grouped by function.

Example: Under W the Type W caviweep is then followed by other types of weep.

Pre-shaped DPC barriers to arrest water-wash withincavity walls to specific areas or features.

Page 38Type Q Arresting barriers

Prevents water contamination via party wall betweendwellings.

Page 37Type PWRB Party wall risingbarrier

Low profile conduits to evacuate arrested water frommasonry features and minimal bed coursings.

Page 44Pyramid Weep Masonry bleed straw

DPC cavitray for stepped and staggered gable abutments. Page 55Advantage Unleaded gableabutment trays

Type B VerticalDPC Cavitray

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problemHow to provide vertical DPC

element to existing cavity wall

where skin changes from

exterior to interior status. (This

product is for vertical use, for

horizontal requirements see

Type E.)

introductionWhen an extension is

constructed, the status of the

walls of the existing building

must be considered.

The installation above roof

level of a DPC is addressed

using the Type E cavitray.

However, the vertical integrity

of the structure is a commonly

overlooked detail and the Type

B vertical DPC can be used

to satisfy this aspect.

solutionThe Type B is a semi-rigid

Polygormac DPC,

manufactured in a range of

preformed profiles. It may be

easily introduced into the

existing exterior skin of a

cavity wall, following vertical

cutting of the masonry to

provide a 4mm slot. (This is

achieved using a disc cutter.)

The penetrating edge of the

Type B is slightly angled and

following pushing into the

newly cut slot, it self-locates

the Type B and provides a

permanent DPC presence

which runs throughout the

masonry skin and into the

cavity. The Type B may also be

incorporated between

proprietary profiles, popular as

a means of linking new cavity

walls with existing cavity walls.

Stainless steel masonry link

profiles are available to

accompany the Type B, thus

providing the complete link

package (see page 119

Cavilinks).

sizesAvailable in 2400mm lengths.

Type B1. Suits standard

brickwork and standard

blockwork skins. Type B2.

Suits 150 mm thickness skins.

Type B3. Suits 225mm

thickness skins.

materialPolygormac DPC.

colourBlack.

installation/site workCleanly cut slot through depth

of existing cavity skin in

position and to height required.

Push leading edge of Type B

into slot and locate as

illustrated. Wrap around

external lip of Type B creates

a weathering finish where

appropriate.

bill of quantitywordingType B vertical DPC for

introduction into existing

masonry skins. Manufactured

by Cavity Trays Limited of

Yeovil, Somerset BA22 8HU

(01935 474769). Introduce

Type B following

manufacturer’s instructions

which accompany every

consignment. Supplied in

standard 2.4 metre lengths.

State if insulated version is

required. Profile required =

............ Number of lengths

required = ............

Request liability/conformity

document upon completion.

ordering/regulationsSee inside back cover for

details.

In situations where a new

window or door-frame of a

conservatory abuts the original

masonry, consider positioning

the Type B so the lip oversails

as shown.

related products andapplicationsThe Type B provides the

vertical DPC element. See

Type E for horizontal DPC.

• Introduces vertical DPC element

• Suitable for traditional or timber frame construction

• Requires minimal masonry slot cutting to install

• Ensures regulation compliance when using profiles

• Shape suitable for mid-cavity and frame edge positioning

• Accompanying optional masonry link profiles

10

Type B Vertical DPCshown fitted betweentwo profiles.

designers’ comments

The Type B addresses anoften overlooked detail inbuilding. Whilst the cavity isnot bridged, the BuildingRegulations still requireadequate protection againstthe passage of moisture.The findings of theinvestigation carried out bythe Building ResearchEstablishment were quitespecific, “ensure a verticalDPC is provided”. The TypeB is intended for use inexisting structures andprovides an easy route ofaddressing the regulations.This product was developedfrom our specialist flashing,previously listed as SF45,the profile and sizes beingthe most popular andsatisfactory in terms ofconvenience of use andreliability.

technicalobservationsSuitable for traditional buildand timber frameconstruction. Preformed shape will notsag or tear. Sizes to suit all external leafthicknesses. Integralweathering edge. Brandedwith name and logo asproof of type andaccompanying warranty.

Original exterior wall becomes aninterior wall when an extension isconstructed. Vertical DPC integrityis required as well as horizontalDPC integrity.

Type B between leaves of cavity wall.

105mm

155mm

230mm

Type B with door-frame

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Type BA CavityBarrier Arch

DPC only

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problemHow to provide a moulded

DPC barrier only for arches,

thus permitting traditional

construction.

introductionEstablished construction

methods using traditional

centring are still required on

some projects, and for such

purposes the Type BA barrier

arch DPC is appropriate.

solutionThe Type BA barrier arch is a

DPC, supplied ready-shaped

to suit the arch opening.

The Type BA is incorporated

within the cavity wall with its

base section positioned on

the traditional centring.

The barrier arch DPC is

normally returned into the

inside skin, at the appropriate

level, in the traditional manner.

On large openings (or

openings with a significant

rise) we can incorporate, if

considered necessary, a

number of stability mouldings

within the upstand of the

DPC. These encourage the

barrier arch to adopt the

correct upright position as

the cavity wall skins are

raised. They are not

positioned at intrados level

and therefore do not obstruct

the cavity compartment area,

which always remains clear.

sizesOur flexible standard design

can be adapted to suit most

requirements and the Type

BA barrier arch DPC is

offered on a tailor-made basis.

Polypropylene with a

thickness of 3mm, 2mm and

1.5mm is used as appropriate

in our forming process.

Maximum overall length

available in one piece is

2400mm. Type BA can

sometimes be supplied in

sections to accommodate

wider arches.

Feasibility/quotation on

receipt of drawings. Stopends

accompany all supplies.

materialPolypropylene.

colourBlack.

installation/site workType BA barrier arch DPCs

should be introduced at the

appropriate stage in

construction, following the

recommendations of BS

5628. Ensure Type BA takes

up correct shape within cavity

and is returned into the inside

skin as per instructions.

bill of quantitywordingType BA barrier arch

manufactured in heavy duty

DPC from Cavity Trays of

Yeovil Somerset BA22 8HU

(01935 474769).

Introduce Type BA barrier

arch DPCs following

manufacturer’s instructions

within all arch openings, being

constructed in the traditional

manner using centring.

Specify number and size of

each Type BA design

required.




details.

• Available in different arch styles and design

• Provides matching DPC element to arch masonry

• Permits traditional centring use

• Traditional or timber frame construction

• Format can accommodate very wide openings

11


BS 5628-3:2005 (5.11.6)correctly identifies that, inarch construction, there areadded complications ofdamp-proofing the junctionbetween inner and outerskin. A conventional DPC cannotreadily be sloped outwardsand simultaneously curvedto follow the outer skin. The Type BA wasintroduced to provide thebenefit of a modern shapedDPC, with the traditions ofconventional archconstruction.If the Type BA is being usedwith timber frameconstruction, it is suppliedwith an appropriatelyshaped top for fixing directlyto the timber inner skin. Thevapour barrier is thenoverdressed to form asatisfactory union as perN.H.B.C. details.

technicalobservationsProvides correctly shapedDPC whilst permittingtraditional construction. DPCelement is establishedwithout doubt, at intradoslevel. Sectioned format canpermit wider openings to beaccommodated.Branded with name and logoas proof of type andaccompanying warranty.

Incorrect construction usingconventional DPC. Introduced in thefirst available horizontal run, thisarrangement is suspect because itleaves a considerable amount ofbrickwork between window and DPCwhich is unprotected.

When supplied to suit alarge opening the TypeBA comprises ofseveral sections. The lower sections arepositioned first andoverlapped by thehigher sections toprevent water pooling.Sealing links ensure abonded relationship.

Type C Cavitrayfor use with lintels over openings

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problemHow to create preformed,

ready-shaped DPCs for use

with proprietary metal lintels.

Ditto for use with cast in-situ,

pre-stressed and pre-cast

concrete lintels.

introductionThe upgraded Type C cavitray

range fulfils the latest British

Standards and NHBC

requirements which demand

an independent DPC to be

used with proprietary metal

lintels in specified locations

and applications. In addition,

Type C cavitrays may be used

to provide the obligatory DPC,

when constructing using

concrete lintels of most styles.

solutionType C cavitrays provide a

harmonizing yet independent

DPC tray to all lintel openings.

Manufactured from solid

DPC. The shape and

functionality of every tray over

every opening is of a

consistent quality. Preformed

Type C trays eliminate the

danger of misplacement and

installation deviances

associated with site

fabrications using roll

materials. Type C trays are

supplied in the profile to suit

your project.

Type C cavitrays are not

limited to one cavity width.

Our design permits numerous

cavity widths to be

accommodated, whilst

maintaining a clear cavity

compartment area. This is

important if the risk of mortar

build-up within the cavity is to

be avoided. Available to order

with each Type C cavitray are

Type L lintel stopends. The

Type L stopends have an

integral anchoring butyl base

which permits them to be

applied in the most appropriate

perp position towards the end

of each Type C tray.

When stopends are applied,

water is prevented from

discharging into the cavity.

Instead, water is directed and

discharged out of the building

fabric via weepvents which

are incorporated within

appropriate perp joints.

Weepvents also permit the

wall to breathe.

On the following page some

examples of profiles available

are shown. All profiles may be

supplied with the cavity

upstand either returning into

the inside skin or terminating

against the face of the inside

skin. If the tray is to return

into the inside skin, this is

easily accommodated within

an appropriate bedding

course. Alternatively, upstands

can finish against the inside

skin face. This is possible

because they are rigid, self-

supporting, and slightly

tensioned take up the

maximum cavity width.

Unlike traditional DPC they

do not require aid to prevent

sagging. Select the preferred

format, taking into

consideration any regional

requirements.

The use of preformed Type C

Cavitrays ensures every

window and door opening is

consistently and correctly

protected every time. The

dangers associated with roll

material: distortion,

misplacement, sagging and

installer error need not arise.

Easy stock control and the

elimination of cutting and

wastage is another

accompanying benefit.

The European Standard for

lintels: BS EN 845.2:2001

qualifies corrosion protection

required in any individual

application, making reference

to “the degree of exposure and

climatic conditions”. We

recommend the use of an

accompanying Type C cavitray

at all times to comply with the

new European Standard, which

is not specific as to where or

when such exposure conditions

apply. Specifying of Type C

cavitrays at all times to ensure

compliance is accordingly

recommended.

sizesSimply advise the shape you

require and it will be

manufactured to suit your

project. Profiles also available

to marry with proprietary lintels

such as Catnic, IG, Birtley,

Harvey, Jones, Keystone, etc. A

Type C cavity tray schedule can

be prepared to harmonise with

any lintel schedule. Standard

• Ready-shaped DPC trays for all lintel styles

• Wastage and inaccurate site fabrication eliminated

• Ensures consistent build details and regulation compliance

• Unobstructed cavity compartment area


• Accurate cost and stock control

12

In accordance with NHBC requirements, a cavity tray should be provided where the cavity is bridged and should extend beyond

each side of the bridge. Type C cavitrays satisfy this requirement. State opening dimension as well as

lintel type and length. This enables us to supply the cavitray to appropriate dimensions to

oversail the end of the lintel and whatever is closing the reveal

(normally 150mm at each end). Lintel shown for clarity.


Type C cavitrays aremanufactured from solidDPC polypropylene. SolidDPC means there is noreliance upon surfacecoatings for protection.Protective measures for steellintels, including provision ofDPCs where appropriate,should comply with BS5977: Part 2. This stipulationis qualified within BS 5628-3:2005 (5.11.6). Experience inmanufacturing Type Ccavitrays has highlighted fourprincipal considerations:-

1) The need for a material tobe sufficiently strong enoughto resist accidental damageduring construction yetsufficiently durable bearing inmind the planned life of thebuilding.

2) A material that should beresistant to stress/creepdeformation, and thus able towithstand the load to beimposed upon it. (creepdeformation is dependentupon the stress(compressive) induced by thestructure weight bearingupon same). The stress is normally gradedinto four classes:-a) High is above 2.45N/mmwhich is generated in wallshigher than 10 storeys.b) Medium in the 0.5N/mmto 2.5N/mm range (4-10storeys high).

The new BS 5628-3:2005stipulates “the cavity tray shouldstep down or slope across thecavity not less than 150mmtowards the external leaf and,preferably, terminate in a small dripon the face of the wall”. The use ofpreformed Type C cavitrays providesan assured method of compliance.

The Type C is self-supporting.There is no need to build into theinner skin. However, an inner skinreturn option is available onrequest. (shown dotted).

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Type C Cavitray for use with lintels over openings

lengths in 2400mm lengths

with siliconbond glove lapping

recommended for making up

longer lengths. Base thickness

1.5mm. Alternative thickness

upon request.

materialSolid polypropylene. Securtex

finish on polypropylene.

colourBlack.

installation/site workBed Type C cavitray in

illustrated position within

steel/concrete lintel ensuring

self-supporting cavity upstand

adopts cavity width (or

alternatively build upstand into

internal leaf). Ensure the Type

C ends extend past the ends

of the lintel, in accordance

with N.H.B.C. requirements.

Incorporate Type L stopends

to suit bonding towards end

of cavitray. Remember to

install weepvents to facilitate

discharge of water from

cavitray. Ensure all construction

and mortar bedding/bonding

complies with the relevant

British Standards. Do not dry

bed at any time. Clean out

leaving tray clear and free of

mortar droppings.

bill of quantitywordingType C cavitray from Cavity

Trays of Yeovil, Somerset

BA22 8HU (01935 474769)

Profile = ......

Incorporate and bed DPC

cavitray in position to service

lintel.

Incorporate stopends and

caviweeps.

Total run in metres, including

laps and overhangs = ...

(Alternatively combine length

and profile schedule with lintel

schedule.)



building regulationsType C cavitrays comply with all

Building Regulations and all

appropriate standards. The

illustrated examples are an

indication of some of the

styles/profiles produced.

In some instances it is

desirable to build-in the cavity

upstand into the inner skin,

whilst in other instances the

levered/hinged profile might

be preferred. (Our

levered/hinged profile provides

a tensioned pressure against

the inside skin.) In Scotland,

Northern Ireland and the Isle

of Man requirements can vary

and customers should select

the appropriate profile/format

to comply with the applicable

standards. In accordance with

N.H.B.C. requirements, a cavity

tray should be provided where

the cavity is bridged and

should extend beyond each

side of the bridge.

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• Suitable for use with GRP lintels

13

c) Low in the 0.1N/mmrange generated in walls upto 4 storeys.d) Minimal being less than0.1N/mm. Typical situationbeing parapet walls.

3) Sheer stress is anotherconsideration and a DPCmaterial is required to havea good bond strength andresistance to deformation (atendency to sliding). Inaddition, a high bondstrength (flexural stress) isrequired to prevent failure ofwall along the plane of DPCcavitray.

technicalobservationsStrong preformed profiles.Adjustable stopends.Numerous cavity widthsaccommodated.Clear cavity compartmentarea.Avoids length wastage.Securtex finish promotessuperior mortar adhesion.Branded with name andlogo as proof of type andaccompanying warranty.

Typical examples of some profiles. Type C cavitrays are suitable for use with a variety of lintels. The profile of each Type Cmay finish against the inside skin, or alternatively be built into the inside skin. This second option can necessitate use of alarger profile to marry with the course height. Always stipulate which version you require.

Used to protect box lintel.

Used to protect box lintel.

Type C Cavitray for use with lintels over openings

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Type C cavitrays satisfy this

requirement.

orderingSee inside back cover for

immediate service throughout

the United Kingdom. Merchant

distribution network.

related products andapplicationsSee type L entry for compatible

stopend. Also see type W

weepvent, Euroweep-vent, beak

weep and small weepvent, all of

which may be used with type C

cavitrays and provide exit routes

for trapped rainwater, via the

masonry perps.

For curved head DPCs, see

Type BA. For load bearing

lintel, see Cavilintel.







14

Timber is straddled by steel lintelin course above. Cavitrays protectat both levels.

The Type C cavitray provideshorizontal protection. Type Lstopends prevent discharge intothe cavity. Water is exhausted viacaviweeps in the perp joints. Thevertical cavicloser terminatestightly under the lintel.

To satisfy the aesthetic demands of the area, traditional timber was required overthe openings of all the external elevations of this property constructed in cavitymasonry. The timber however was not capable of providing the requisite loadbearing qualities. Support is provided by a steel lintel immediately above thetimber, which extends 150mm past each end of the timber. Thus the timber is notsubjected to any load bearing demands. A Type C cavitray protects the lower-leveltimber, in anticipation it might be susceptible to water ingress in the long termfollowing timber shrinkage and settlement.

Without an accompanying protective tray this lintel installation fails to comply withUK Building Regulations and European Standards. Protection rising 150mm within the cavity is required. It should also overhang thelintel ends sufficiently to provide shelter to the reveal closing arrangement andideally accommodate stopend and weep discharge provision. Note the block workinner skin does not offer an ideal course in which to support conventional (floppy)dpc. Consequently more material is required. In contrast, preformed Type C cavitrays overcome such problems. Type C trays areready-shaped and supplied to lengths to harmonize with the lintel schedule. TypeC trays are also self-supporting. Compatible stopends and weeps form part of thecompliant answer for all common openings in cavity walls.


NHBC Standards 2010(External masonry walls 6.1D6 b) state that a cavity trayshould provide dripprotection to door andwindow heads. Uniform andconsistent drip protectionusing a preformed Type Ccavity tray is assured.

The angle and lip dimensionscan be predeterminedwhereas such quality andaesthetic control using rolldpc is not possible.

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Cavicloak preformed damp courses

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problemHow to create preformed

moulded cloaks for use within

cavity walls. Cavicloaks are

shaped to exactly fit the

construction detail intended.

Cavicloaks are offered in a

wide range of popular sizes.

Also tailor-made to suit

specific applications.

introductionThe use of preformed

cavicloaks eliminates the

need to fabricate on site.

The ready-moulded units

provide correctly fitting

harmonizing components

which ensure DPC integrity

to features such as corners,

columns, steps and angles.

solutionCavicloaks are moulded from

solid polypropylene A1 DPC.

The material is supple yet

self-supporting. Preformed

units offer flexibility, without

sagging or distorting.

Additional support is not

required to the joints.

Cavicloaks are overlapped

150mm and then further

united using 100mm wide

link-seal strips which promote

positive jointing with the

adjoining appropriate DPC or

cavity tray system. Cavicloaks

are available to suit a wide

range of cavity widths.

Options include the self-

supporting cavity upstand

terminating within the cavity

or alternatively the self-

supporting upstand returning

into the inside skin,

depending on application.

Preformed cavicloaks provide

the reliable alternative to

cutting and fabricating on

site. Cavicloaks ensure

perfect stock control,

eliminate all waste and

permit the architect and

contractor to schedule

accurately, thus eliminating

the possibility of

installer/fabricator error.

cavicloak lengthsThe preformed profile of

each cavicloak is available in

long lengths, if it is desired

not to use traditional roll

DPC between units. Specify

clearly if this option is

required.

pipe cavicloaksService pipe entry point

cavicloaks are available in a

range of sizes. Service pipe

entry cloaks are

manufactured in one piece,

with an accompanying

integrity sealing strip which

is applied around the cloak

to seal the cloak outlet.

sizesStandard cavicloaks are

available to suit most popular

construction details.

Purpose-made cavicloaks are

available to suit special

applications. The following

information is required:

Cavity width.

Upstand vertical rise within

cavity, ie 150mm, 225mm or

other.

Upstand termination option.

Any other relevant information.

Cavity Trays Limited will be

pleased to schedule and

calculate requirements for

any size of project. There is

no charge for this service for

which we are responsible for

component selection.

Component schedules for

client approval are issued.

materialSolid Polypropylene

preformed A1 DPC. Securtex

surface finish. Origination

thickness 1.5mm.

colourBlack.

installation/site workBefore commencing building-

in, we recommend all

components are placed in

position to ensure suitability

and fit. Ensure relationship

with any adjoining DPC or

tray system is correct.

Components may then be

removed and installation may

proceed, observing good

building practice/

BS5628/BS8215. Always

bed on mortar, do not dry bed.

Ensure surfaces of cavicloaks

and any adjoining tray or

DPC system are completely

clean and dry and overlap the

cavicloak 150mm minimum.

Apply self-adhesive link-seal

• Ready-shaped modular DPC cloaks

• Modular components eliminate site fabrication variances

• Accurate scheduling and stock control

• Upstand termination option (self-supporting or return into inner skin)

• Ready to use - no wastage

Illustration shows a changeof level cavicloak in position.


The ability of cavicloaks toself-support offersadvantages as productapplication may beindependent of the internalskin if so desired. Theupstand termination optionpermits versatile use withcast concrete, structuralsteel and timber-frameinside skin/cavityprojections. Cavicloakspromote constructioncontrol and consistentquality.

technicalobservationsPreformed mouldedcomponents.Link-seal jointing.Upstand termination option.No distortion or sagging.Efficient site scheduling andstock control.Branded with name andlogo as proof of type andaccompanying warranty.

15

The cavicloak expansion link permitscontinuation of DPC integrity but withexpansion and contraction provision.South and west facing elevationscommonly suffer more thermal gainand masonry expanses should bedesigned to take into accountpossible movement potential.

Cavicloak preformed damp courses

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strip over entire overlap, so

that strip is equally positioned

on the cloak and on adjoining

medium.

Fixing instructions

accompany all consignments.

If in doubt do not proceed but

seek advice immediately by

telephoning our Help Desk

on 01935 474769.

bill of quantitywordingSelf-supporting cavicloaks

from Cavity Trays Limited of

Yeovil, Somerset BA22 8HU.

(01935 474769). Sizes as

schedule prepared by Cavity

Trays Limited. Bed preformed

cavicloaks within horizontal

mortar joints at the appropriate

course level as work proceeds.

Follow carefully the installation

instructions which accompany

every consignment. Ensure all

installation is strictly in

accordance with the

manufacturer’s instructions.




details.

related products andapplicationsDrainage of water from

cavicloaks is recommended

via perp weeps of which there

are three options.

See Type W Weepvent,

Euroweep-vent, beak weep

and small weepvent.

Cavicloaks may be linked to

our sitesealer membranes

when incorporated to protect

the oversite, see Type N.

If cavicloaks are to be used to

act as steps and corners

linked to traditional rolled

DPC, consider Caviroll

Premium DPC. Alternatively,

long preformed straights may

be utilised which are available

to match the cavicloak

profiles.

• Ready-shaped modular DPC cloaks

• Modular components eliminate site fabrication variances

• Accurate scheduling and stock control

• Upstand termination option*

• Ready to use - no wastage

SPEPCC/SEP/0100

Step down cloak(Small step) CC/LC/080

Type C/P with pipe projectingthrough cloak CC/CP/0360

Cloak aroundvertical vent sleeve

CC/CS/0440CC/CS/050

StopendCC/SE/0160

External AngleCC/EC/0380

Column cloakCC/C/0450

Window Cill tray(Dependant on size)

CC/UC/0350

Windpost Cloak(Handed)

CC/WRS/0290Internal Angle CC/IC/0370

Stopend CC/SE/0410

Windpost cloakCC/WC/0430

Column cloakCC/C/0400


Change of profile(Frame) cloakCC/FC/0420

Threshold CavicloakCC/S/060


Column CavicloakCC/C/090

Level Change /External corner Cavicloak

CC/S/0110

Stopend cavicloak CC/SE/040

Cloak over ventCC/SCC/0330

Change ofProfile Cloak

CC/COP/0190

Step down cloak (Large step)

(150mm - 600mm High)CC/LC/0340

Party Wall link cavicloakCC/PWL/0220

Windpost CloakCC/WC/0280

Windpost CloakCC/WC/0300

Radon Internal AngleCC/RAD/IC/0250

Change of Profile / Change ofDirection / Change of Level

CC/CLCP/IC/0270

Internal AngleCC/IC/0320

Corner Column Cloak(2 piece unit supplied)

CC/CEC/0240

Change of Level /Change of Direction

CC/SLIC/060

Column Cloak(Supplied in two pieces)

CC/CC/0270

Radon External AngleCC/RAD/EC/0260

Step down cloak (Small step)CC/LC/030

Typical examples from range. Cavicloaks can be supplied to customer’s dimensions.

*Illustration shows a change

of level cavicloak that requires

building into exterior skin only.

(Upstand is self-supporting)

16


The ability of cavicloaks toself-support offersadvantages as productapplication may beindependent of the internalskin if so desired. Theupstand termination optionpermits versatile use withcast concrete, structuralsteel and timber-frameinside skin/cavityprojections. Cavicloakspromote constructioncontrol and consistentquality.

technicalobservationsPreformed mouldedcomponents.Link-seal jointing.Upstand termination option.No distortion or sagging.Efficient site scheduling andstock control.Branded with name andlogo as proof of type andaccompanying warranty.

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Type CD CavityDropcloaks

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problemHow to DPC protect a high

level masonry feature of the

outer skin of a cavity wall, in a

manner that does not weaken

or affect the structural bonding

of the skin in question.

introductionCavity wall integrity is

dependent on the cavity status

being maintained. Where

intentional projections and

restrictions exist within a

cavity wall, cavity dropcloaks

ensure penetrating water cannot

permeate beyond such

projections or restrictions.

Cavity dropcloaks introduce

a barrier isolating the inner

skin, whilst being independent

of the outer skin. Thus the

structural bond of any external

masonry feature is unbroken.

This is particularly important

where dentils or corbelling

are featured.

solutionType CD Cavity Dropcloaks

are preformed DPC units built

into the inner leaf of a cavity

wall. They isolate the inner leaf

from outer leaf. They may be

employed where masonry

horizontally steps or where

projections exist within the

cavity. Where masonry

features such as dentils or

corbels are incorporated, one

might normally expect the

DPC measures to be

incorporated in the external

skin rather than the inside

skin. However, with a minimal

amount of external skin

masonry bearing on the DPC

at high level such interruptions

weaken the masonry mass. In

comparison dropcloaks avoid

such interruption so structural

integrity is maintained.

Type CD Dropcloaks may be

used in both timber-frame and

traditional construction. Where

fire or acoustic barriers are

incorporated, dropcloaks

prevent penetrating water

bridging the cavity via such

barriers. Similarly where

separating floors of concrete

break the vertical continuity of

a masonry inner skin

dropcloaks may be used to

satisfy the obligatory damp

protection requirements.

Compared with the textbook

approach illustrated, the use of

dropcloaks additionally

safeguards against mortar

bridging between concrete and

external skin.

sizesExamples of popular sizes are

illustrated. Most profiles

accommodate cavities 50mm

to 100mm. For clarity always

specify actual cavity width.

Also available in dimensions to

suit specific requirements.

materialPetheleyne.

colourBlack.

installation/site workCavity Dropcloaks should be

incorporated at the


construction following good

practice and recommendations

of BS5628 and Robust Details.

Build into inside skin or secure

against inside skin (if timber-

frame) as per instructions that


bill of quantitywordingType CD cavity dropcloaks by

Cavity Trays of Yeovil, Somerset.

BA22 8HU. (01935 474769).

Profile: stipulate. Incorporate

at level shown following


Type CD cavity dropcloaks

……..metres run. Angles

internal …number. Angles

external ……number.

ordering/regulationsSee inside back cover.

related products andapplicationsSee also Arresting Barriers

and Type C Cavitrays for damp

protection. See Type CFIS for

cavity barriers/fire stops.

• DPC control independent of external masonry skin

• Uninterrupted structural bonding of outer skin

• Traditional and timber-frame compatibility

• Available in all dimensions

Where horizontal cavity stops orbarriers are also incorporated to complywith Robust Details Part E, Dropcloaksprevent penetrating water tracking onthe top surface of the barrier.

Cavity dropcloaks protect high-leveldentil coursing and intermediatestrings. The masonry bonding of theexterior skin is not interrupted. (1752)


There are addedconsiderations where acavity is fully filled orpartially filled. Where theinner face of the externalskin is not maintained inone vertical plane becauseof a masonry feature orstability arrangement,always take addedprotective measures.Similarly, where the externalskin is of a material thatdeviates in depth (example:stone that projects randomlyinto cavity) additionalprotection is essential.Failure to do so will result inwater ingress, as dischargewill be directed into thebody of the insulation ratherthan against it in the case offull fill, and possibly againstthe insulation in the case ofpartial fill.

technicalobservationsBranded with name andlogo as proof of type andaccompanying warranty.

17

Cavilintel lintel with integral security shutter

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problemHow to provide load bearing

lintel over openings, with

retractable integral shutter

facility.

introductionThe Cavilintel is designed for

use with cavity walls. Unlike a

traditional metal lintel, the

Cavilintel can accommodate a

shutter within its main body.

Selection of a Cavilintel

instead of a conventional lintel

makes little difference to

construction procedure when

a property is built. However,

the Cavilintel does extend to

the developer or property

owner the additional option of

being able to upgrade the

property with a vandal-

resistant shutter, either

immediately or at some time

in the future.

solutionAll Cavilintels are

manufactured to size on a

tailor-made basis. Each is

supplied packaged to include

all the requirements

commonly necessary to create

a structural opening,

accompanied with the damp-

proofing obligations as defined

within the latest BS5628 -

3:2005. The contents of each

Cavilintel package are:

Load bearing metal Cavilintel

with compartment area ready

to receive shutter.

Preformed DPC cavitray with

self-supporting cavity upstand

to provide horizontal protection

against penetrating rain.

Type L stopends to prevent

discharge of water into the

cavity. Dual-function Type W

perp caviweeps/cavivents to

evacuate water from the

structure.

Reinforced and insulated

guide channels to close the

cavity reveals each side of the

opening and accommodate

the ends of the shutter.

Preformed DPC sill tray to

provide damp-proofing

integrity at sill level.

Electrically operated shutter

with a manual override

mechanism within the

building. (Shutter fitted and

commissioned by engineer

immediately or at some time

in the future if the property is

being offered with the option

of security upgrade.)

The reinforced insulated guide

channels eliminate the

requirement for conventional

reveal closing. Each guide

channel is positioned in the

cavity, behind the external

masonry leaf. Thus the

structural opening and the

window or door-frames are

not inhibited with protruding

surface mounted fittings and

fixings. When the shutter

descends or ascends, the

metal linings within the

channels provide positive

retention of the ends of the

shutter and promote easy

movement.

The Cavilintel requires the

window or door-frame to be

set-back in the reveal opening,

behind the guide channel. All

frames must be free of front

projections that might foul the

path of the shutter. The set-

back frame position

necessitating DPC integrity is

also established at sill level

and this function is provided

by the accompanying sill tray.

Thus the unique composite

package offered by the

Cavilintel provides the

complete solution, and

addresses important damp-

proofing and water evacuation

design considerations. The

Cavilintel package does not

leave them as aspects

requiring site fabrication.

The Cavilintel is handled and

bedded in the traditional

manner applicable with metal

lintels, additionally observing

the slot in the Cavilintel base

(through which the shutter

operates) is aligned with the

corresponding guide channels

that rise vertically within the

reveal cavities.

The Cavilintel is supplied with

an open back. Following

commissioning of the shutter

the building contractor may

panel over and insulate the

open back in whatever way

appropriate to suit the project.

We recommend all panels are

removable to facilitate any

future maintenance.

The insulated channel guide is

available to suit cavity widths

of 50mm, 75mm and 100mm.

The channel has locators to

aid envelopment within the

reveal and is anchored to both

skins with special ties. The

surface area of each tie is

unusually large and promotes

solidity of encapsulation. The

guide has polymer brush-seals

to the outer edges and a metal

security channel in which the

ends of the vandal-resistant

shutter glide up and down.

shuttersThe vandal-resistant shutter is

electrically operated. With the

option of a manual control to

permit operation from within

the building in the event of a

power failure. When

• Lintel with built-in facility for vandal-resistant shutter

• Clear structural opening unobstructed by guides or surface fixings

• Complete installation requirements including cavitrays, weeps, stopends, DPC

• Benefit of property upgrade immediately or at a later date

18


The package fulfils thedamp-proofingrequirements as definedwithin the new Code ofpractice for the use ofmasonry, part 3, materialsand components, designand workmanship. (5628-3: 2005). The profile towhich the lintel productadheres was originally thesubject of a recordedapplication priority date of1981 and publication dateof 1983. The channel guideis based on CT SF112.

technicalobservationsBranded with name andlogo and proof of type andaccompanying warranty.

The Cavilintel addresses all aspects of load bearing, cold-bridging,damp-proofing and securityrequirements.

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Cavilintel lintel with integral security shutter

completely lowered the

individual security slats lock

down into place to maximise

strength, rigidity and impact

resistance. Shutters may also

be partially lowered or raised

to act as a sun visor.

Shutter slats are extruded in

solid aluminium and each slat

consists of a centre void with

two converging solid faces

providing a maximum overall

thickness of 8mm. We do not

fit lightweight aluminium

folded or skinned slats to

Cavilintels.

sizesStandard applications up to

3.6 metre lintel length.

Profile dimensions are

generally varied to suit the

wall specification, and to take

into account any unusual

features or point loadings.

The shutter drop (opening

height) dictates the size of the

lintel compartment that

accommodates the shutter

when coiled. Some long drop

applications necessitate a

larger compartment that can

extend past the internal

plaster face. Access for

maintenance is easy via the

open back.

materialAustenitic stainless steel EN

10088.

Zinc coated steel BS EN 845-

2:2001.

Polystyrene insulation BS

3837.

DPC cavitrays to BS 5628-

3:2005.

Weeps/stops as defined BS

8000-3:2001.

Bitumen coatings: 100

microns.

coloursNatural steel or colours to

order.

Shutter slats available in 36

colours.

installation/site workFull instructions for the

handling, storage and

installation of the Cavilintel

and accessories accompany

every order. An electrical

supply to each Cavilintel is

necessary and provision

should be made at the time of

construction. Full details and

requirements are scheduled in

our method statement that

accompanies all offers of sale.

bill of quantitywordingCavilintel complete vandal-

resistant opening package

from Cavity Trays of Yeovil,

Somerset, BA22 8HU (01935

474769). Opening dimensions

.....wide x ....high in cavity wall

consisting of (state outside,

cavity and inside skin

dimensions). Number............


details.

related products andapplicationsFor curved openings, see

Type BA.

further considerationThe Cavilintel package is

complete, and includes

accompanying cavitray

protection as defined by the

latest European Standard BS

EN 845.2:2001. The Cavilintel

package should not be

confused with alternatives that

do not offer the benefit of

stopends, caviweeps and

cavitray protection.

phone01935 474769 fax


cavitytrays.co.uk

• Lintel with built-in facility for vandal-resistant shutter

• Clear structural opening unobstructed by guides or surface fixings

• Complete installation requirements including cavitrays, weeps, stopends, DPC

• Benefit of property upgrade immediately or at a later date

19


The package fulfils thedamp-proofingrequirements as definedwithin the new Code ofPractice for the use ofmasonry, part 3, materialsand components, designand workmanship.(BS5628-3: 2005). Theprofile to which the lintelproduct adheres wasoriginally the subject of arecorded applicationpriority date of 1981 andpublication date of 1983.The channel guide isbased on CT SF112.


Caviroll Premium DPC

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• British Standards general purpose roll DPC

• Durable, tough and puncture resistant

• Wide temperature scale flexibility

• Gripgrid surface

• Impermeable and homogeneous

20

problemThe requirement of a general

purpose DPC suitable for

horizontal and vertical damp-

proofing of cavity walls.

introductionThe functional requirement of

a DPC incorporated within a

wall is to act as a barrier

against the passage of water,

whilst accommodating

expansion, contraction and

thermal changes of the

building structure. Premium

Caviroll DPC is designed for

such purposes and applications.

solutionPremium Caviroll DPC is

manufactured from solid

polyethylene which conforms

with BS 6515. It promotes

excellent tensile strength and

retains flexibility through a

temperature range of -50

degrees up to +80 degrees

centigrade.

Premium Caviroll DPC is a

homogeneous material,

possessing superior water

impermeability. Both sides of

the DPC have a gripgrid

surface to promote adhesion

and unity with the mortar.

Premium Caviroll DPC is a

clean and easy to handle

material which is tough,

flexible and resistant against

acidic and alkaline elements. It

provides an economical

method of satisfying the

requirements of the Building

Regulations, using a material

manufactured to BS 6515.

sizesAvailable in standard 30 linear

metre rolls, in the following

widths:-100, 112.5, 150, 225,

300, 337.5, 375, 450, 600,

900mm. Thickness 0.5mm.

materialPolyethylene, gripgrid surfaced.

colourBlack.

applications/installationsCaviroll DPC must be

carefully unrolled and laid on

mortar, observing the

guidelines of BS8000, Part 3,

1989. When using Caviroll as

a DPC at ground level in an

external skin on a sloping site,

ensure the Caviroll is stepped

to suit. Always fully bed on an

even flushed-up level surface

of mortar, and ensure there is

immediate continuity of mix

and laying of the course above

the DPC. Always lay

continuous lengths for the full

width of the masonry leaf.

Keep any joints to a minimum

and cleanly lap 150mm. The

weight of the masonry course

above the Caviroll when laid

immediately following the

placement of the DPC will

help promote good adhesion

between mortar, masonry and

damp course.

In a cavity wall with separate

Caviroll DPCs in each leaf,

ensure edges do not project

into the cavity. The horizontal

Caviroll DPC should preferably

protrude slightly externally, in

accordance with BS8000. The

edge of the DPC should never

be covered with mortar.

Always select the Caviroll in a

size to adequately cover the

total width of the masonry in

which it is to be installed,

when creating horizontal DPC

at ground level.

technical/mechanical detailsNo water-absorption.

Waterpermeability -

0.00036 kg m2h atm.

Tensile strength - 1.266

kg/mm2. Tearing elasticity -

800%. Temperature scale -

flexibility from -50 degrees up

to +80 degrees centigrade.

bill of quantitywordingPremium Caviroll DPC to

BS6515, from Cavity Trays of


(01935 474769). Lay Premium

Caviroll DPC to architect’s

detail, in accordance with good

building practice. Do not dry

bed. Observe manufacturer’s


every consignment.

Total area in sq metres=.....

or alternatively

Total run including laps at

.....mm girth =.....




BS 6515 qualifies that DPCshall consist of black low-density polyethylene sheethaving a mass in the rangeof 0.425 kg/m2 to 0.54 kg/m2,formed from a polyethylenepolymer of a melt flow rateof 5 or less when measuredaccording to BS 2782:Method 720A and having adensity within the range of0.915g/mL to 0.925g/mL at23 degrees centigrade whentested in accordance with620A, 620B or 620D of BS2782. Methods 620A to620D: 1980. The product iscompatible with our FlashingAnchoring System and doesnot extrude under pressure.

technicalobservationsBritish Standard DPC withgripgrid surface.Impermeable. High tensilestrength and elasticity. Not for use below copingsand in parapets.

Roll width

100mm112.5mm150mm225mm300mm

337.5mm375mm450mm600mm900mm

M2 per30m roll

3.003.3754.506.759.00

10.17511.2513.5018.0027.00

WeightKg

1.281.441.922.873.834.814.795.747.6511.48

Either flush orprojecting slightly

Do not create aledge here withthe DPC

150mm

The profiles will not extrude

under load and functionality

is unaffected by normal

packing / point loading.

Additional protective rise can

be specified where a double

soleplate is used. Internal

and external angles are

similarly preformed. Bespoke

profiles are available in

addition to the standard

profiles.

sizes108 x 108 x 2400mm

108 x 150 x 2400mm

Matching angles 300mm x

300mm

Other dimensions on request

materialSolid polypropylene dpc

colourBlack

bill of quantitywordingDPC profiles by Cavity Trays

Ltd Yeovil Somerset BA22

8HU (01935 474769).

Fit and lap to all sole plates.

Total run metres…… Angles

no…….

related products andapplicationsFor applications where the

dpc arrangement extends to

embrace radon barrier control

and thermal insulation within

traditional cavity construction,

see Type GBFICS Ground

Bearing Floor Insulating

Cavitray System in separate

publication: Closing Cavity

Walls.


details.

problemTimber frame construction

standards demand dpc’s are

incorporated below all sole

plates of all ground floor walls.

Similar demands apply to

SIP’s. Maintaining a correct

and consistent dpc profile is

essential, as is accurate

placement. Traditional dpc can

distort and misshape. It is also

easily damaged during

construction.

introductionType DPC Profiles are

accurately dimensioned semi-

rigid shaped dpc’s that permit

the installer to establish

consistent dpc protection

around the base of timber-

framed walls and wall panels.

solutionLaid and lapped under the

sole plate, DPC Profiles rise

vertically to protect the inner

face of the plate. (Depicted in

NHBC Standards 6.2). They

can also extend inwardly. In so

doing the oversite membrane

can benefit both horizontal

and vertical interfacing.


In addressing therequirements for airtightness, Robust Detailscalls for the dpc behind asole plate to turn up andlap with vapour controllayer. DPC Profiles can beused effectively to achievethis relationship (manualreferences 6.11 to 6.15inclusive). Whenconstructing on radonemitting ground, it ispossible to utilise a one-piece soleplate thatadditionally extendsdownwardly in the cavityand outwardly through thecavity wall. Manufacturedfrom (gas grade) pethylenedpc, it provides a way ofaddressing severalregulation aspects in oneoperation. Enquire via theCavity Trays Helpdeskservice.

DA

MP

-PR

OO

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G

Type DPC Profiles SIPS Panel DPC Profiles

Timber Frame (DPC) Profiles

phone01935 474769 fax


cavitytrays.co.uk

• Satisfies NHBC / Robust Details requirement

• Will not extrude or seep under load

• Close fits timber – no sagging or damage

• Consistent quality of build

21

Standard 90° profile

Extended 90° profile

External corner

Internal corner

yy

Type E Cavitray for insertion into existing walls

DA

MP

-PR

OO

FIN

Gphone

01935 474769 fax01935 428223 em

[email protected]

problemTo damp-proof an original

outside wall which has

become an inside wall by

virtue of an extension being

built. Also suitable for

remedial work where an

existing DPC has failed.

See next product entry

describing Type E for remedial

and corrective applications.

introductionWhen an extension is added

to a building, the problems of

inserting a DPC at the

horizontal intersections must

be faced. By present methods

this is not an easy operation.

In many cases complete

strutting is necessary. In all

cases the amount of brickwork

which must be cut away to

permit the insertion of a DPC

extends to 300mm or more in

depth. This means four

courses of bricks for the whole

length of the DPC. In the case

of the shored wall, there is

considerable making good to

brickwork, plasterwork, ceiling

and decoration. The use of the

Type E cavitray overcomes all

these problems.

solutionThe Type E is a preformed

DPC unit, two bricks in length.

There are upstands at either

end of each tray that clip

together. Trays are inserted

into a cavity wall one at a time.

Long runs are thus created

with a series of connected

but self-contained Type E

units. The preformed ends

coincide with masonry perp

joints. No reliance is therefore

placed on gluing or sticking

adjoining lengths - an exercise

that can be difficult when

inserting any DPC medium.

All Type E cavitrays have an

extended cavity upstand that

runs the length of the tray.

The upstands automatically

adjust for any cavity width

from 50mm up to 140mm,

ensuring compatibility with

the cavity encountered.

The front projecting lip of

each tray is designed to

provide protection of the

bedding course against wind-

driven rain. Apart from the

financial saving, the advantages

of the preformed Type E

cavitray are considerable. There

is no shoring and therefore no

making good, thus workmen do

not need to enter the building.

Only one course of brickwork is

disturbed therefore no large

scar remains after insertion.

Time taken to install represents

a small fraction of time taken

by the traditional method. The

awkward and sometimes

suspect running joints of a

normal DPC or tray installation

are eliminated.

The adjustable cavity upstand

accommodates the ‘as built’

cavity status rather than the

anticipated status. Type E

cavitrays are extensively used

on commercial, industrial,

educational and domestic

extension work.

sizesThe standard cavitray sizes

shown suit most brick

dimensions. The unique U clip

design enables adjoining trays

to be slightly ‘adjustable’ to help

match existing bond. Please

compare your brick size with

our standard tray size. Notify us

should you require alternative

dimensions, such as to

accommodate old imperial

bricks. Trays can be supplied in

almost any special size.

materialPolypropylene solid DPC,

injection moulded to ensure

uniform thickness. Trays can

also be supplied in other

materials to suit special

applications.

colourBlack.

installation/site workCut out masonry in the

external skin of cavity wall in

accordance with the

installation instructions

provided by Cavity Trays of

Yeovil. Insert one at a time

into the existing external skin.

Incorporate flashing under

cavitray if appropriate.

• Brick-sized cavitrays permit progressive insertion

• Anticapil interlocking to form long runs

• Cavity widths compatible - upstand adjusts to suit

• Unobstructed cavity compartment area with stand-alone discharge

• Easy compliance with building regulations

• Minimal disturbance to masonry - fitted from outside

22

Only one course is cut out to accommodate the Type E Cavitray.


The positive upstand jointingbetween trays wasestablished many years agoas our most reliable format.We rejected overlapping andsticking as, in our tests itproved less reliable as theintegrity of the adhesion/joinin the cavity spanning portionwas unsupported and, beingan existing wall, theaccess/working space tomake the overlap was limited. The superior results weobtained when anticapilclipped together dictated weadopt the cavitray with endupstands. It is interesting tonote that each tray beingself-contained, meanspinpointing of any areaproblem can belocated/identified withaccuracy and speed - not aneasy task with thealternative stick together/open run format. The rigidpanoplied lip has provedessential in exposedapplications and highintersections. Stopends andweeps promoted inBS8215:1991 and the latestBS 5628:3-2005. Thesefeatures have formed part ofour Type E system for manyyears, thus Type E cavitraysmore than satisfy the lateststandards. Type E cavitraysalso have a cavity upstandheight of 150mm to satisfythe standard requirements -a dimension which is notmatched by allmanufacturers.

Rain penetrates the external skin,which becomes an internal skinbelow the new roofline.

Type E cavitrays with extended flexibleupstands are particularly suitable fornon-standard or varying cavities.

DA

MP

-PR

OO

FIN

Gphone

01935 474769 fax01935 428223 em

[email protected]







23

yy

Replace bricks into the

cavitray within the wall.

Ensure tray and all bricks are

correctly bedded in mortar.

Slate pin to make safe and

firm. Incorporate weepvent in

the middle of each cavitray.

Adjoining trays clip together

automatically. Continue

operation until required run is

completed. Ensure all

installation is strictly in

accordance with manufacturer’s

instructions.

bill of quantitywordingType E cavitray from Cavity


BA22 8HU (01935 474769).

Size as standard (or specify

size of tray required).

Total run in metres = ........




details.

related products andapplicationsSee entry under Type E

Remedial for solving dampness

problems within existing

structures.

For new-build horizontal

applications see Type G entry.

Type E Cavitrays discharge

arrested water via perp

weepvents - see entries for

Type W weepvent, Euroweep-

vent, beak weep and small

weepvent.

technicalobservationsPositive jointing integralanticapil clip eliminatesgluing, sticking oroverlapping. Shape anddepth of projecting lipprevents discharge waterpermeating the beddingjoint - an often overlookedconsideration on exposedsites. Adjustable cavityupstand accommodatescavity size variations.Unobstructed tray cavitycompartment. Featuresclassify Type E cavitray ashigh performance.Branded with name andlogo as proof of type andaccompanying warranty.

Type E cavitrays used with a leadflashing, where a new roof abuts anexisting wall.

Step 2 - One cavitray is insertedtogether with the flashing intended fordressing over the skirting of the rooffinish (flashing approx 50mm intowall). Lead flashing is not required inmost remedial applications.

Step 3 - Two bricks are replaced inthe wall into the cavitray. They arejointed and securely slate pinned,leaving the wall above safe and firm. A weepvent is incorporated in themiddle perp. Two more bricks areremoved again forming a three brickspace. The flashing is extended and asecond cavitray inserted. The integralU clip joins the trays, ensuring that nowater can penetrate. Two more bricksare inserted and a weephole againformed. There are now two adjoiningbut completely self-containedcavitrays. The method is continueduntil the required run is completed.(Always bed on mortar. Do not dry bed.)

Step 1 - Three bricks are removedfrom the wall forming a 675mmopening (an angle grinder/cutter isideal for cutting out).

2

2

3

3

4

54

1

1

Type E External Angle Right Hand Type E External Angle Left Hand

Type E Internal Angle Left Hand Type E Straight 450mm Long Type E Internal Angle Right Hand

218

113

450

330

225

327 215

228

116

State size of tray required .....

Cut out masonry in the

external skin of the cavity wall

in accordance with installation

instructions provided by Cavity

Trays of Yeovil. Insert one at a

time into existing external skin.

Replace bricks into cavitray

within the wall. Incorporate

weepvent in the middle of

each cavitray. Ensure every tray

and all bricks are correctly

bedded in mortar and slate pin

to make safe and firm.

Adjoining trays clip together.

Remove adjoining brick.

Continue operation until

required run is completed.

Clearly specify all angles and

sizes. Total run in metres

equals ..... Request

liability/conformity document

upon completion.


details.

yy

problemHow to introduce an effective

DPC into an existing cavity

wall in which the original

damp-proofing element has

been omitted, damaged,

incorrectly formed or is

suspect/faulty.

introductionExisting cavity walls rely upon

the use of damp courses to

maintain dry status of the

inner skin and dry status of

the exterior skin whenever an

intersection creates a change

of level. In the past

conventional damp courses

have been used on high-rise

developments and when

building cavity walls “off the

solid” or “off a ringbeam”.

Unfortunately, conventional

damp courses do not permit

the easy (and often

satisfactory) creation of

intricate construction details.

Overlaps and joints fail, and

unsupported laps spanning the

cavity provide a weakness via

which collected cavity water

may penetrate. Junctions with

piers and columns are often

precariously, incorrectly, and

inconsistently fabricated on

site. When dampness is

eventually experienced, there is

an urgent requirement to

regularize construction

economically and with the

minimum of disturbance.

The Type E cavitray is designed

for such applications.

solutionDetails of our Type E cavitrays

are described on the previous

pages. When used in remedial

situations, the minimum of

exterior masonry is disturbed

(normally one course only).

The Type E cavitray is a self-

contained stand-alone unit

with its own collection area

and discharge outlet (via a

weep/vent). It is therefore

easy to identify and address

specific areas and runs. This

advantage is not available

with other systems. The Type

E cavitray for use in remedial

applications may be supplied

in various lengths, widths and

depths. Thus the external skin

masonry module encountered

on site may be matched. Long

runs of trays are easily created,

whilst maintaining self-

contained and stand-alone

status. Installation is from the

outside of the building only.

sizesSpecify whether you require

the standard cavitray size or a

specific size to suit the length

and depth of the masonry

module of which your building

is constructed.

materialPolypropylene solid DPC,

injection moulded to ensure

uniform thickness.

colourBlack.

survey serviceWe will be pleased to visit

sites and advise on the most

appropriate size of tray to suit

your project.

bill of quantitywordingType E cavitray from Cavity


BA22 8HU (01935 474769).

Type E Cavitray for remedial/refurbishment works

DA

MP

-PR

OO

FIN

Gphone

01935 474769 fax01935 428223 em

[email protected]







24

Type E cavitrays used without flashing,over an existing opening where theoriginal damp course has failed or hasbeen omitted. The exact course inwhich the cavitray is introduced variesdepending on the construction detail.

The Type E is availablein an infinite choice ofwidths and lengths.

Examples of purpose-made trays whichaccommodate cavitycolumns.

(See previous page for Type E general details).

Only one course is cut out to accommodate the Type E Cavitray.


Standard insertion ofcavitrays to regularise existingconstruction that has failedor is not protected againstdamp ingress does notinvolve fixing to or insertioninto the inner skin. Thus thestructural quality andairtightness of the inner skinremains undisturbed.

Where existing masonry withan undulating face isencountered, bring the finishof the course onto which thetrays are to be bedded to astraight and even status, topermit uniform and correctrectrofitting.

DA

MP

-PR

OO

FIN

G

Type F Corrugated Flashing

for use with PVC corrugated sheeting

phone01935 474769 fax


cavitytrays.co.uk

• Fills and flashes sheet top with masonry

• Adjusts to suit different roof angles

• Blends with roof finish

25

Type F standard 3 inch profile.Type E cavitray can be fitted athigher level if required

problemHow to create corrugated

flashing suitable for use with

plastic roof sheets only.

introductionIt is a difficult task to

adequately join or flash the

gap between the top of a

translucent corrugated roof

and a wall. Examples can be

seen everywhere of cracking

cement fillets, accumulations

of mastic, and applications of

tape which will not stretch into

the sheet profile and up the

wall without creasing and

causing difficulties.

solutionThe new Type F corrugated

flashing units can be used on

porches, lean-tos, outhouses,

conservatories, or temporary

structures having lightweight

translucent corrugated roof

sheeting. The Type F flashing

unit incorporates a unique

integral hinge, usually making

it suitable for any angle of roof

from 17.5° up to and including

60°. The units are fixed simply

by positioning before securing

the top of sheet fixings, which

then hold the units in place.

The Type F fits the

corrugations snugly, whilst the

upstand springs to shape

vertically against the wall.

The upstand can then be

finished off with either:

1 Type E cavitray (if a room

and Building Regulations

stipulate).

2 Standard cover flashing

tape or conventional lead or

aluminium cover flashing.

size of wall flashingsType F flashing units are

available in the following

profiles:

Standard 3”/75mm asbestos.

Standard 3”/75mm iron.

Miniature.

Grecca box profile 76/18.

Box profile 16mm.

Box profile 14mm.

Onduline standard profile.

Onduline isoline U18.

Approximate dimensions

150mm x 85mm upstand x

715mm lengths. (Units

purposely designed to a length

slightly shorter than width of

standard sheet to prevent all

overlaps coinciding and

contributing to heat

discolouration.)

Non-standard sizes available

to order.

type F corrugated ridgeThe Type F corrugated ridge is

designed to act as a one-part

ridge on structures

incorporating translucent

roof sheets.

The ridge provides a simple,

neat and inexpensive way of

uniting and finishing

corrugated sheets which meet

in an apex format. Type F

corrugated ridge flashings are

suitable for roof pitches of 17.5

degrees up to 60 degrees.

size of ridge flashing700mm x 160mm each side.

(Units purposely designed to a

length slightly shorter than the

width of a standard sheet, to

prevent all overlaps coinciding

and contributing to heat

discolouration.) Standard

3”/75mm asbestos profile.

materialPVCU classified “self-extin-

guishing”. Onduline profile

available in black poly-

propylene, toning grade only.

colourNatural translucent. Onduline

profile available in black only.

installation/site workIn storing, handling and fixing

of units, one should exercise

care and attention as specified

and exercised with standard

translucent roofing sheets.

Follow sheet installation

instructions. Corrugated units

are fixed simply by positioning

before securing the top of

sheet fixings, which then hold

the units in place. Observe

standard sheet overlap

dimensions.

bill of quantitywordingType F corrugated flashing

unit or corrugated ridge from

Cavity Trays of Yeovil,

Somerset BA22 8HU

(01935 474769). Unit to be

fixed in accordance with


Corrugated flashings to be

secured at top of sheets prior

to securing the top of sheet

fixings. Total measured run

including laps =......... Request


upon completion.


details.

related products andapplicationsConsider use of Type E

Cavitray within the wall above

the Type F flashing unit if the

structure is to be damp-

proofed within the definition of

the Building Regulations.

technicalobservationsCorrugated flashings suitangles of roof from 17.5degrees up to 60 degrees. Lightweight appearancematches roof sheets.Easily and simply fixedusing standard roofsheetfixings.Branded with name andlogo as proof of type andaccompanying warranty.

Type FAS flashing anchoring and DPC integrity system

DA

MP

-PR

OO

FIN

Gphone

01935 474769 fax01935 428223 em

[email protected]

problemHow to secure flashing in

position and ensure correct

linking with conventional DPC.

introductionThe FAS flashing anchoring

and DPC integrity system is

designed to overcome

problems which can occur

where flashings are turned

into walls of brick and stone,

constructed with or without a

conventional DPC material.

Incorporated by the bricklayer

whilst raising the wall, the

Type FAS provides the facility

for the flashing to be correctly

located and secured at a later

date, whilst promoting the

correct DPC/flashing

relationship.

solutionMade of stainless steel and

fitted by the mason, the Type

FAS provides a positive recess

into which the flashing is

located. It avoids the need for

subsequent chopping out of

the mortar joint and the risk of

damage to the brick, stone or

damp-proof course.

The integral barbs grip the

25mm turn-in of the flashing

and eliminate the need for

lead wedges. When pointed

with silicone sealant the joint

accommodates differences in

thermal movement and

prevents the cracking and

falling out that commonly

occurs when mortar is used in

restricted pointing

applications. The FAS avoids

damage to the DPC, and

ensures the recess into which

the flashing is secured is

under the DPC at all times.

The Type FAS makes flashing

fixing easy and positive.

sizes2000mm x 65mm x 6/16mm.

The FAS can also be supplied

with a larger jaw, to

accommodate thicker lead

flashing (i.e. above codes 4 & 5).

further considerationsThe rebuilding or the

construction of new parapet

walls in solid wall or cavity

format may incorporate the

Flashing Anchoring Strip to

create the channel and fixing

medium into which the lead

flashing may be introduced at

a later date. The amount of

masonry above the flashing

intersection is often limited

and conventional lead wedging

can result in the masonry

above being ‘lifted’ or

disturbed. The Type FAS

addresses this problem and

eliminates the need for such

wedging.

materialAustenitic stainless steel.

colourSelf-coloured stainless steel.

installation/site workBed Type FAS in mortar at

appropriate course level.

Ensure adjoining lengths are

butted together. Front turn-

down lip should be tight

against the masonry which

aids correct alignment. Ensure

mortar is levelled and true

when trowelled to the top

surface of the Type FAS

before the introduction of a

DPC (where fitted). Ensure

front receiving slot is kept

clean. When mitre cutting

corners ensure jaw gap is

maintained. At a later date the

plumber should install lead

flashings observing the LSA

guidelines. Apply flexible

pointing medium (Siliconbond)

to slot to complete installation.

bill of quantitywordingType FAS flashing anchoring

and DPC integrity system


Somerset BA22 8HU

(01935 474769).

Bed Type FAS in position at

appropriate course level,

observing instructions which

accompany every consignment.

(See Installation/Sitework.)


butted together and corners

are appropriately mitred.

Total run in metres = .....


details.

related products andapplicationsThe Type FAS is for use with

lead flashings - see pages

dealing with Lead Fabrications

and Supplies.

For discharging of the

arrested water see Type W

weepvents, Euroweep-vents,

beak weep and small

weepvents. As an alternative

to introducing lead flashings at

a later date within the build

programme, preformed

cavitrays may be supplied with

lead flashing already attached.

See Type G which deals with

horizontal applications.

• Provides uniform slot to receive lead flashing

• Eliminates chopping-out and damage to DPC

• Anchors flashing within wall

• Eliminates wedging and associated problems

26

The Flashing Anchoring Strip may be used with Premium Caviroll DPC


The Type FAS is primarilyaimed for use with wallsincorporating conventionalroll DPCs or for walls inwhich DPCs are notincorporated. The Type FASeliminates chopping out ofthe mortar and subsequentdamage of any DPC if fitted.Conventional wedging of thesubsequent flashing iseliminated and a uniformslot to receive Siliconbondcaulking or similar iscreated. The Type FAS isdesigned for use oncommercial and industrialconstruction and is notcompatible or necessarywhen using our approvedcavitrays with attached leadflashings. Our general policyis to recommend the use oftrays with lead flashingsalready attached. Wheresuch an approach is notpossible, consideration ofthe Type FAS should begiven.

technicalobservationsEliminates chopping out ofmortar and damage ofDPCs.Eliminates wedging.Self-secure integral barbs.Branded with name andlogo as proof of type andaccompanying warranty.

25mm 40mm

25mm 40mm

Lead flashing is secured bythe barbs within the jaw, andSiliconbond pointed at alater date.

DA

MP

-PR

OO

FIN

G

Type G Cavitray general-purpose cavitray for changes of level and building off the solid or ringbeam

phone01935 474769 fax


cavitytrays.co.uk

• Easy and fast building-in with brickwork sized units

• Adjoining lengths interlock

• Adjustable upstand ensures cavity width compatibility

• Traditional or timber-frame construction


• Establishes consistent build quality detail

27

Type G is available with an attachedlead flashing (example 300mm.) Inthis example the flashing issufficient to dress directly over theabutting roof tiles.

yy

problemFormation of a reliable DPC

system for general-purpose

applications including

changes of level, diaphragm

walls, porch and garage roof

intersections, building off the

solid, junctions with bay

windows etc.

introductionThe Type G cavitray is

designed for general-purpose

horizontal applications. It is

supplied in preformed lengths

and preformed angles, all of

which have end upstands.

Long runs of tray are easily

created as adjoining section

ends unite and secure

together within the perp joint.

Thus a positive union is

established. The Type G

cavitray is available in three

styles. All the Type G versions

feature an adjustable upstand

(shown above) within the

cavity, which accommodates

cavity widths from 50mm up

to 150mm.

solutionThe Type G cavitray is

manufactured in standard

900mm lengths. Infill or

special lengths to suit

specific runs are also

available. Thus the use of the

Type G cavitray can eliminate

waste and aid efficient and

cost-effective stock control.

Each tray has integral

stopends and is therefore a

self-contained unit. Linking

adjoining trays creates long

runs. An integral caisson

lock-link on the stopend

moulding permits this to be

done instantly and positively.

Gluing and sticking by site

operatives is eliminated.

Standards are thus not

dependent on the man on

site who may not be trained

or able to maintain 100%

consistency or accuracy.

Preformed trays are available

to accommodate angles or

piers where they are

encountered. Thus the

protective tray detail is

maintained throughout the

installation.

Type G cavitrays may be

supplied with a lead flashing

already attached. This offers

several further advantages.

It eliminates the need to deal

with the flashing as a separate

site operation. It also

establishes beyond doubt that

the union between tray and

flashing is correct and

positive. The mason is also

saved the task of having to

return to site at a later date

to point-in the union.

The cavity upstand that rises

from each tray is rigid, self-

supporting yet fully adjustable.

The upstand may be adjusted

to suit cavities from 50mm up

to 150mm. Should the cavity

width deviate, the Type G

upstand can vary to suit. The

upstand does not require

building-in to the inside skin.

Therefore the inside skin may

be of concrete blockwork,

brickwork, cast concrete or

timber frame. The Type G is

always compatible.

The collection and dispersal

of arrested water within the

wall is in compliance with

industry recommendations.

Each tray is a self-contained

unit with stand-alone

evacuation of water via a

weephole. Type G cavitrays

may be used with any of our

approved caviweeps.

sizesStandard profile suits most

brickwork sizes incorporating

cavities from 50mm in width

up to 150mm in width.

Standard lengths of 900mm,

675mm, 450mm plus infill

lengths as required. Standard

profile as illustrated. Internal

and external angles are

manufactured to stated sizes

unless otherwise scheduled.

When required with a lead

flashing attached to the tray,

please specify the amount of

lead to be left projecting and

the lead weight (example:

150mm of code 4 lead left

projecting). When supplied


The Type G cavitrayemerging panoplied lipprovides protection to thebedding course - a feature which cannot beachieved with conventionalfelts and polymers. Trayssatisfy the requirements ofBS5628, BS8215 andNHBC requirements.

Each Type G cavitray is aclosed-circuit unit, withstand-alone collection anddischarge behaviour.Weep/vents permit cavitywater evacuation and cavityventilation. Because thecavity upstand is hinged andof a tensioned nature, itaccommodates the as-builtcavity status rather than theas-intended, whilstmaintaining a clear cavitycompartment area.

The Type G may also beused within diaphragmwalls. The widened cavityand structurally connectingbrickwork cross-ribs of thediaphragm wall accept thecavitray which limits thepossible water “pooling” toan area just within the cavityvoid. DPCs in a diaphragmwall must not travel across tothe inside skin. Trayupstands are built throughconnecting cross-ribs.

Universal external angle. 220mm x 220mm.For convenience, this angle is not handedand may normally be used for mostexternal angle applications.(External angles specifically left or right -handed are available to special order)

Universal internal angle. 120mm x 120mm.For convenience, this angle is not handedand may normally be used for mostinternal angle applications(Internal angles specifically left or right -handed are available to special order)

Adjustable cavity upstand.

*Standard product accommodates cavity up to 150mm.Specify flap extension for cavities up to 200mm.

*

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with an attached lead

flashings, allowance is

automatically made for

flashings to overlap adjoining

flashings. Special angles,

corners etc., to accommodate

piers and columns are

available.

non-standard sizesBespoke service operates.

Adaptations available to suit

non-standard dimensions and

applications, including wide

front-to-back dimensions as

encountered with stonework etc.

materialPetheleyne solid damp-

course. Lead flashing to

BSEN 12588, 1999.

colourBlack.

Lead flashing, natural.

installation/site workType G cavitrays should be

bedded in mortar, and

masonry bedded onto trays.

Do not dry bed. Ensure

weep/vents are incorporated

within the external skin at

tray level. Two weeps per tray

length. Always position weeps

towards centre of tray. Ensure

all joints are made positively

and the cavity upstand takes

up the correct position.

bill of quantitywordingType G general-purpose

cavitray from Cavity Trays of


(01935 474769).

Size as standard (or specify

size of trays required). Specify

size of attached lead flashing

(if appropriate).

Bed Type G cavitrays on

mortar as work proceeds.

Observe usual codes of

practice and standards.

Incorporate weepvents

minimum of 2 per cavitray

length.

Schedule of tray lengths = ....

(number) x 900 = ....

Infilling lengths = .... (number x

.... (length) = ....

Number of internal angles = ......

Number of external angles = ......



Linking with other trays Type

G cavitrays can be used and

linked with Type X cavitrays.

Reference is made within the

Type X cavitray pages.


details.

related products andapplicationsFor existing walls see Type E.

Type G general purpose

cavitrays require weepvents

for water discharge. There

are three styles available, see

Type W weepvent, Type

Euroweep-vent, Beak weep

and Small weepvent.

Type G Cavitray general-purpose cavitray for changesof level and building off the solid or ringbeam

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• Easy and fast building-in with brickwork sized units

• Adjoining lengths interlock

• Adjustable upstand ensures cavity width compatibility



• Establishes consistent build quality detail

28

Type G is available with an attachedlead flashing (example 300mm.) Inthis example the flashing issufficient to dress directly over theabutting roof tiles.

technicalobservationsPart L airtightness of theinner skin is not compromised.The cavity upstand of thetray does not enter orinterfere with the bonding.

Accommodates numerouscavity sizes.Suitable for traditional buildand timber frameconstruction.Projecting panoplied lipensures integrity alongbedding course.Integral stopends ensurecorrect termination of theDPC tray against piers, etc.Unrestricted cavitycatchment compartmentmoulding does not projector encourage mortarbridging.Positive uniting sections notreliant on site gluing andsticking.Self-supporting. Eliminatesnecessity to line up outerand inner support courses.Trasson cavity upstand risesto correct height.Branded with name andlogo as proof of type andaccompanying warranty.

Type G cavitray with lead attachedused at a change of level to ensurethe horizontal intersection is correctlydamp-proofed and weatherproofed.

Unlipped Type G cavitray used as anarresting barrier, to minimise cavitywash within the cavity wall. Thisarrangement invisibly reduces thepenetrating water volume at a levelabove a critical junction. Appropriatewith some masonry details andcommonly used over projecting stringcourses and features (see separateentry dealing with arresting barriers).

Type G cavitray used in ringbeam/concrete frame situation. The endupstands terminate against the verticalcolumns. The protective panoplied lipprotects the bedding course.

Type G provides the horizontal protection and Type X the stepped protection

Type G cavitrays with attached leadflashings provide protection to thefront horizontal intersection. Note theType X trays used above the slopingabutment terminate with an externalangle. This provides a protective linkwith the Type G trays.

* Standard product accommodates cavity up to 140mm.Specify flap extension for cavities up to 200mm.

*

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Type J DPCSupport and

Closer

phone01935 474769 fax


cavitytrays.co.uk

• Insulates and closes the cavity

• Supports the DPC

• Prevents water pooling under coping

• Satisfies BS 5628 requirement

29

The Type J is available eitherinsulated or uninsulated.

problemHow to provide DPC support

and close cavity under parapet

copings. Also how to provide

means of closing cavity in

open eaves and other eaves

details.

introductionParapet construction requires

a DPC immediately under the

coping. BS5628:Part 3

qualifies the manner in which

the DPC must be supported.

The Type J closer fulfils the

requirements of the British

Standard, and also the NHBC

performance standard,

chapter 6.1, S4 (c) to (d).

solutionThe conventional cavity

parapet is normally terminated

with copings, under which a

DPC is bedded and positioned.

The width of the DPC must

be sufficient to slightly

overhang the width of the

parapet masonry. Support of

the DPC is required where it

crosses the cavity. The Type J

is designed for such purposes.

Thermal movement dictates

that slight fractures occur in

coping joints, but the provision

of a DPC, adequately and

uniformly supported, normally

overcomes associated

problems (frost damage,

interstitial condensation and

water penetration).

The Type J can also be used

for closing the cavity in other

applications, such as in open

cottage-style eaves where

joists leave limited space for

the cavity to be uniformly

terminated. BS 3837/1986

polystyrene insulation 0.37

typical thermal conductivity.

The Type J is available in an

insulated form. A 25mm

polystyrene inlay is provided

between the two downward

projecting locators.

The insulation K-value is

0.037 W/m°C. The overall

insulated version performance

is dependent upon the size of

cavity in which the profile is

incorporated. If used as a

screed support at a cavity

threshold, the Type J should

carry a screed of sufficient

density and thickness to

provide solidity to prevent

cracking.

sizesThe Type J DPC

support/closer is now

available in two sizes.

J1 = 130mm x 30mm x

2mm/2.5mm.

J2 = 150mm x 30mm x

2mm/2.5mm.

Standard lengths 2400mm.

The dimensions of the J1

closer make it suitable for use

in cavities from 50mm up to

and including 90mm.

The J2 is a larger closer and

is suitable for use in cavities

from 90mm up to and

including 130mm. The Type J

can be supplied in other sizes

to suit specific requirements.

materialExtruded PVCU, type 4.

colourContract white.

installation/site workType J closers should be

bedded in mortar, as per the

code of practice which applies

to the installation of damp

courses in masonry

construction. The projecting

legs help locate the closer.

Adjoining lengths should be

butt jointed to provide a

uniform and even plane.

bill of quantitywordingType J cavity support/closer


Somerset BA22 8HU

(01935 474769).

Standard J1 or J2 (or state

special size required).

Carefully place and mortar

bed in position following



butt jointed, cut and mitre

corners to suit. Specify overall

length required (standard

2400mm lengths). Request


on completion.


details.

related products andapplicationsType J support closer may be

used with Type P Cavitrays for

parapet walls - see separate

entry. Caviroll premium DPC

may be considered for use

between copings and Type J.

See Type X for sloping

abutments.

Observe requirement of

NHBC and Zurich Municipal

guidelines and consider

coping stone mechanical

fixings if appropriate. See

Designer’s Comments listed

under Type P Cavitray which

refer to structural stability.


The Type J is an enhancedversion of a metal closer,previously designed andmanufactured by thiscompany. The two profilesare now in extruded PVCU,and to revised dimensionswhich make them suitablefor a wider range of cavitywidths. Thus this improveddesign satisfies NHBC,Zurich Municipal and BritishStandards, includingBS8215:1991 (5.5).

Application suitability isincreased with newmoulding dimensions. Theinsulated versions addressinterstitial condensation, andmay be considered for usewithin construction wherematerials of mixed/varyingheat loss qualities areincorporated.

technicalobservationsLocates, supports andcloses cavity.Numerous cavity widthsaccommodated.Eliminates wastage.Branded with name andlogo as proof of type andaccompanying warranty.

Type J insulated version. Insulation is contained between the

two downstands

Type J1

130mm

30mm

30mm

Type J2

150mm

90mm

45mm

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Type K CircularCavitray DPC cavitray for circular bullseye windows

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problemHow to correctly damp-proof

circular openings.

introductionWhenever a circular bullseye

window is installed, the

builder faces the difficult task

of providing correct DPC

protection. A conventional

horizontal damp course

leaves vulnerable areas which

readily accept and transmit

dampness. Ideally, the damp

course should follow the

shape of the circular window

and provide 360° protection.

This is achieved with the

circular Type K cavitray.

solutionThe Type K cavitray is

manufactured from solid

DPC and is supplied in one

piece ready to receive the

circular window. It fits snugly

around the window frame,

providing a 360° barrier. The

circular window is

immediately enveloped in a

durable cavitray thus ensuring

correct and thorough

protection.

The inside skin of the cavity

wall and the sides of the

circular window frame are

protected from dampness.

The unique design of the

Type K cavitray

accommodates numerous

cavity widths and numerous

frame positions. The cavitray

travels vertically downwards

within the cavity, until it

passes the bottom of the

circular window. At this point

the base projects forward so

any arrested water is directed

away from the inside skin.

Type W weepvents may be

incorporated to aid cavity wall

ventilation if appropriate.

thermal zoning (optional)

Positioning of a circular

window mid-cavity is one of

the most economical

methods of build and permits

the introduction of a circular

polystyrene thermal collar.

Thus a thermal zone is

introduced to the perimeter

of the entire frame. The collar

is manufactured in

dimensionally stable

polystyrene, with a typical

thermal conductivity figure of

between 0.037. Specify Type

K plus thermal collar to fulfil

both DPC cavitray and

thermal zoning requirements.

sizesAvailable to suit most popular

circular window sizes.

Sizes supplied include

470mm, 600mm, 630mm,

675mm, 700mm, 750mm,

800mm.

Perimeter gussets allow a

degree of frame size

tolerance. Special sizes and

other sizes available.

materialThermo-stable polypropylene

DPC type 6, heavy-duty.

colourBlack.

installation/site workIntroduce window frame into

protective sleeve of cavitray.

The Type K should be built-in

at the appropriate stage in

construction, following the

recommendations of

BS5628. Ensure Type K

takes up correct shape within

cavity and is returned into the

inside skin as per

instructions.

bill of quantitywordingType K cavitray for circular

openings manufactured in

type 6 heavy-duty DPC from


Somerset BA22 8HU

(01935 474769).

Incorporate Type K cavitray

DPC following


Specify number and size of

each Type K cavitray required.




details.

related products andapplicationsSee Type BA which provides

DPC for curved head

openings. For perp ventilation,

see Type W.

• Horizontal and vertical DPC in one unit

• Enveloped 360 degree protection

• Permits continuity of cavity installation

• Frame position options

• Range of sizes

30

Type K provides 360ºprotection.


GBG33 published by theBRE in September 1999draws attention to theimportance of DPCs aroundopenings. It qualifies howwater must be preventedfrom reaching the insideskin, and the manner inwhich vertical DPCs mustbe lapped to prevent wateringress. Circular openingsrequire particular attention. By combining vertical andhorizontal protection on onemoulding unit, the Type Kaddresses all objectives.Thus the common areas ofweakness are eliminated.

technicalobservations360° total protection.Suits numerous cavitywidths.Accepts forward or mid-frame positions.Isolate frame edge fromdirect masonry contact.Cavity insulation maycontinue across front ofcavitray.Branded with name andlogo as proof of type andaccompanying warranty.

SectionthroughType K

Type K ThermalCollar inpolystyrene.

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Type L Lintel Stopends phone

01935 474769 fax01935 428223 em

[email protected]

• Adjusts for secure fit

• Ensures consistent and compliant build detail

• Integral bonding strip in base

• Suits wide range of styles and shapes

31

The adjustable Type Lcan be used with mostpopular shapes of lintel,cavitray and DPC.

yy

problemHow to create lintel stopends

for use at the ends of most

popular DPC steel lintels to

prevent discharge of water

into the cavity. Stopends may

also be applied to a range of

cavitrays, DPCs and barriers.

Now recommended by

NHBC and BS8215: 1991.

introductionThe use of Type L lintel stopends

quickly and economically

introduces a lintel feature

which removes the problems

and dangers that might

otherwise be experienced

with volumes of water being

directed into the cavity.

solutionStopends are available in two

standard styles to suit most

popular lintels and lintel

damp courses, cavitrays etc.

Incorporated into the

moulded base of the lintel

stopends is a butyl anchoring

strip, which enables stopends

to be secured towards the

end of lintels etc, in the most

appropriate position to suit

the masonry perp joint.

Stopends do not disrupt the

bond. When fitted, discharge

from lintels is directed

through brickwork weeps,

and reference should be

made to weepvents. These

fulfil the weep function whilst

also helping to reduce the

pressure difference between

the two surfaces of the outer

leaf. This can directly dictate

a slight reduction in the

amount of water penetration.

Weepvents also promote

ventilation of the cavity.

The presence of cavity

insulation or fill can change

the behaviour of water within

the cavity, whilst sites which

are severely exposed can

introduce further criteria. The

new NHBC standards and

BS8215 refer to the use of

lintel stopends to prevent

water running back into the

construction. NHBC clauses

now qualify that a cavity tray or

lintel should receive lintel

stopends, in accordance with

its directive. The Building

Research Establishment

defect action sheet (DAS98)

states, “If stopends are not

used on cavity trays or lintels

acting as cavity trays, rain

water discharge particularly

in cavity filled walls, may wet

the inner leaf, producing

dampness of internal walls”.

“Consider specifying stopends

or cavity trays acting as

stopends as recommended.

Stopends are essential where

cavity fill is to be installed and

very desirable elsewhere.”

sizesSpecial sizes for non-

standard applications or skin

thickness available.

materialDurrpolyethylene 6/A.

colourBlack.

installation/site workEnsure the surface of lintel is

clean and dry. Remove

protective covering to

anchoring seal on bottom of

stopend. Position to suit perp

joint nearest the very ends of

the lintels/DPC/cavitray.

bill of quantitywordingType L Durrpolyethylene lintel

stopends from Cavity Trays

Ltd of Yeovil, Somerset BA22

8HU (01935 474769). The

type of lintel/DPC/cavity tray

being used must be clearly

specified to ensure the

correct size/type of Type L

lintel stopend is supplied.

State style of stopend if

known .... Apply stopends to

ends of lintel in accordance

with manufacturer’s

instructions.

Total number of stopends = .....




details..

related products andapplicationsType L Lintel Stopends should

be used with weepvents to

permit water discharge.

See Type W, Euroweep-vent,

small weepvent and beak

weep.


Stopends are nowrecognised as a necessity. In1989 the B.R.E. publishedtheir report, “ThermalInsulation.... Avoiding Risks”. (See 1/SfB(A3j)(M2)). This report confirmed andrecommended theprecautions, which CavityTrays Ltd have for manyyears advised meritedincorporation for long termintegrity of construction. Ourrecommendations werevindicated by this report. In1994 the NHBC issued adirective that stopends mustbe used with lintels. Theeffect of stopends is tocreate self-contained DPCunits with their owndischarge outlets. Thisconcept was originallydeveloped by Cavity TraysLtd in 1959, when a rangeof tray styles, each withintegral stopends was madeavailable. 35 years after thisoriginal development workthe use of stopends with DPCs has become anobligatory undertaking. Stopends now form part ofthe new British Standard5628:3-2005.


The adjustable Type L can servicea wide range of sloping upstandsand cavity widths.Cavities 50mm to 100mmmaximum on 150mm upstand rise.Cavities to150mm on 225mmupstand rise.

Type L90 This stopend has a 90°upstand and is used with lintels,trays and damp-courses risingvertically in the cavity.

Lead Fabrications and lead supply services

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problemLead is still one of the most

acceptable materials for the

manufacture of some special

flashings for the building

industry. It has very high

ductibility, malleability and

corrosion resistance.

We can supply it pre-cut and

preformed to suit a variety of

applications. Our lead working

department will be pleased to

advise you and supply

leadburned flashings and

products to specification.

solutionThe preformed flashing used

when a soil or other pipe

penetrates a pitched roof of

tiles, slates or contoured roof

sheets, is called a lead slate.

Cavity Trays Limited has

developed a special version of

a lead slate, which we term a

Coneslate.

The Coneslate is

manufactured with a tapered

pipe sleeve. This tapering is

most beneficial in terms of

storage (and reduction of

subsequent damage). The

shape also permits the

Coneslate to be used upon a

variety of roof pitches from

20° up to 40°. Use of the

Coneslate removes the

necessity for the

contractor/plumber to

purchase conventional slates

to suit the specific roof pitch.

Telescopic stacking enables

quantities of the Coneslate to

be stocked, in the knowledge

that the wide range of roof

pitches accommodated

removes the danger of

obsolescence.

sizesConeslates available in code 3,

code 4 or code 5 weight.

Standard pipe size 100mm x

115mm upstand. Base size

400mm x 415mm depth.

(Contoured roofing sheets

may require a larger base

size.) Roof pitch: our standard

Coneslate of 30° is

manufactured to permit a

tolerance of ± 10°, thus this

lead slate is suitable for all roof

pitches from 20° up to 40°.

bespoke leadworkThe illustrations shown are

representative of some of the

many lead fabrications which

are produced by our

craftsmen. We will be pleased

to quote for specific lead

requirements manufactured

from British Standard cold

rolled milled lead fabricated by

our specialists to L.S.A.

guidelines.

lead supply serviceA lead supply service operates,

supplying a wide variety of

lead weights in rolls and cut to

size pieces. Contact our lead

sales department to

determine the daily lead

supply price and availability.

materialRolled lead sheet to the latest

standard BSEN 12588:1999.

Stipulate lead weight required

for any item or fabrication.


details..

• Standard and bespoke fabrications

• BSEN 12588 material

• Width to 2400mm

• Various lead weights/thickness

32

Our new Coneslate,suits pitches from 20°up to 40°. Coneslatescan be stored easily asthe shape permitstelescopic stacking.


At the end of 1999, thefamiliar BS 1178 for leadsheet was superseded. Thenew standard for rolled leadsheet is BSEN 12588:1999. This new standard avoidsconfusion with cast methodsof lead sheet, which are notembraced by this newstandard. Cavity Trays Ltduse only genuine rolledsheet lead, to the newBSEN 12588:1999, asrecommended by the LSA.

technicalobservationsBritish standard coldrolled milled leadfabricated by establishedspecialists to L.S.A.guidelines.

BS Code No. : 3Colour Code : GreenThickness mm: 1.32Weight Kg/m2: 15.00lb/ft2: 2.91

BS Code No. : 4Colour Code : BlueThickness mm: 1.80Weight Kg/m2: 20.41lb/ft2: 4.19

BS Code No. : 5Colour Code : RedThickness mm: 2.24Weight Kg/m2: 25.40lb/ft2: 5.21

Stanchionslates

Fixing blocks

Head flashingassembly within tile hanging

Lead butterflycrossover

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Type LTT Level Threshold Tray

(Threshold Isolation DPC)

phone01935 474769 fax


cavitytrays.co.uk

• Isolates damp masonry

• Easy interfacing of horizontal and vertical arrangements

• Increases flooring and insulation options

• Standardised protection detail ensures integrity

33


A new British Standard wasreleased in December2009. BS 8102 provides theCode of Practice for theprotection of below groundstructures against waterfrom the ground. Section6.2 states waterproofingprotection falls into threeclassifications:

1 Barrier protection. 2 Structurally integral

protection.3 Drained protection.

The Type LTT LevelThreshold Tray whilsttechnically a cavity wall dpc,performs twixt levels belowand above ground. In sodoing it embraces thequalities of 1 + 2 + 3,promoting combinedprotection as highlighted inBS 8102, 6.2.2. Cavitymasonry is able to drainconventionally yet beisolated against damptransference whilstpermitting interfacing withthe adjacent structure.Where radon or methanegas is present, a differentstyle of LTT is available thatadditionally closes the cavityand links with adjacentcavity barriers.

problemHow to protect level and

conventional thresholds

against damp and ensure the

threshold dpc, the vertical

closing dpc (closer) and

flooring arrangement can

interface and maintain

protective integrity at the

point of convergence.

introductionThe Level Threshold Tray is a

preformed dpc that

encapsulates the opening

masonry exposed to damp

penetration or subject to

damp infusion. In so doing

the transmittance of damp

from the exterior skin

inwardly or from the inner

skin upwardly is prevented

and the flooring arrangement

can safely interface.

solutionThe Type LTT is manufactured

in solid petheleyne dpc and is

available in a range of sizes to

suit the dimensions of all

standard openings. A bespoke

service operates for non-

standard sizes.

The Type LTT acts as a

threshold dpc and extends

downwardly over both faces of

the masonry. At either end of

the tray the protection rises, and

wraps around the reveal faces*.

In isolating one of the areas

most susceptible to damp

transference, the Type LTT

permits abutting flooring,

abutting insulation and dpc’s

/ membranes to continue

over an inner skin and

converge with an exterior

skin that itself is isolated

from dampness at the point

of convergence. The oversite

membrane is able to

terminate against the Type

LTT and maintain functional

integrity. Importantly the

Type LTT also regularises the

manner in which the vertical

closing of the reveal

interfaces. It is compatible

with our range of

Caviclosers and together

they provide a systematic

and consistent approach to

construction of openings

within cavity walls.

Once bedded on the inner

skin, the Type LTT requires no

further attention. Interfacing

may proceed. The same

applies with the external skin,

although there are two

options regarding how the

installation is finished off on

the external face:

(1) The visible downward

projecting section below sill

level can be left in position to

interface within the gap

provision between any

abutting paving or ramp.

(2) Alternatively it may be

removed along a separation

indentation just below the sill,

leaving a small protective

bedding lip, as highlighted

within BS5628 A.5.3.2.5.

*The outer skin end wraps

challenge rain pooling

adjacent to the threshold

from permeating where

masonry and entrance paving

or ramp surface meet. These

wraps may be trimmed to

some extent at either side of

the opening. The downward

dropping section is usually

hidden by the abutting

ramp/external surface.

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Type LTT Level Threshold Tray(Threshold Isolation DPC)

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optionThe LTT can be used with

most styles of conventional and

level threshold. If you require

the dpc to also rise behind the

sill, an accompanying protective

dpc section provides this option

although it is not necessary in

most styles of construction.

sizesAvailable in dimensions to

accommodate all popular

opening sizes. State

measurements A & B and C.

A = masonry opening

dimension.

B = masonry skin thickness.

C = 150mm or 200mm drop

option.

Tailor-made service operates

for non-standard dimensions.

materialPetheleyne solid dpc

colourBlack

bill of quantitywordingType LTT Level Threshold

DPC Tray by Cavity Trays of

Yeovil Somerset BA22 8HU

(01935 474769). Bed on

threshold masonry skins to all

openings.


details.

related products andapplicationsSee Type TST for alternative /

optional entrance floor

protection.

• Isolates damp masonry

• Easy interfacing of horizontal and vertical arrangements

• Increases flooring and insulation options

• Standardised protection detail ensures integrity

34


A new British Standard wasreleased in December2009. BS 8102 provides theCode of Practice for theprotection of below groundstructures against waterfrom the ground. Section6.2 states waterproofingprotection falls into threeclassifications:

1 Barrier protection. 2 Structurally integral

protection.3 Drained protection.

The Type LTT LevelThreshold Tray whilsttechnically a cavity wall dpc,performs twixt levels belowand above ground. In sodoing it embraces thequalities of 1 + 2 + 3,promoting combinedprotection as highlighted inBS 8102, 6.2.2. Cavitymasonry is able to drainconventionally yet beisolated against damptransference whilstpermitting interfacing withthe adjacent structure.Where radon or methanegas is present, a differentstyle of LTT is available thatadditionally closes the cavityand links with adjacentcavity barriers.

A

B

C

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Type M Cavitray for use over meter boxes

phone01935 474769 fax


cavitytrays.co.uk

• Self-supporting upstand adjusts to cavity widths



• Ensures compliance with guidance standard

35

Type M Cavitray for use over meter boxes.

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problemPreformed cavitray for use

over standard meter boxes

(gas or electricity).

introductionThe Type M cavitray provides

horizontal protection against

damp penetration where a

cavity wall accommodates an

electricity or gas meter

consumer supply control unit

(meter box).

solutionThe Type M cavitray is

manufactured to suit the

standard size box now

extensively used on most

housing developments.

The electricity and gas

apparatus within consumer

meter boxes must be

maintained in an environment

free of damp etc. Dampness

must also be prevented from

reaching the inside skin of

the cavity wall, via the

‘bridging’ consumer unit. The

Type M cavitray fulfils these

requirements.

The length of each tray suits

standard meter boxes and

provides sufficient overhang

to each side. The base of the

Type M suits standard

thickness exterior skins of

brickwork, blockwork, etc.,

whilst the cavity upstand of the

Type M automatically adjusts

to suit most cavity widths

from 50mm up to 140mm.

Type L stopends and

weepvents are compatible

with the Type M.

sizesStandard tray length 600mm.

Standard profile as illustration.

Cavity upstand overall height

150mm. Cavity upstand

adjusts to accommodate

cavity sizes from 50mm up to

140mm.

materialPolypropylene.

Lead BSEN 12588:1999.

colourBlack.

installation/site workType M cavitrays should be

bedded in mortar and

masonry bedded onto trays.

Do not dry bed. Ensure the

cavity upstand takes up the

correct position. Position in

first appropriate course above

meter box.

bill of quantitywordingType M cavitray from Cavity


BA22 8HU (01935 474769).

Standard size Type M cavitray

(or state any special

requirements). State whether

flashing attached is required.

Bed Type M cavitray on

mortar as work proceeds.

Observe usual codes of

practice and standards.

Total standard number

required = .....




details..

related products andapplicationsFor stopends which

harmonize with the Type M,

see Type L. For water

discharge from the Type M

via perps, see Type W

weepvent, Euroweep-vent,

beak weep and small

weepvent.

For general-purpose

horizontal intersection

applications, see Type G

Cavitray. Standard external

meter boxes issued by the

Gas and Electricity

Companies have an external

surround, the top section of

which can trap water.

Consider sealing/filling this

using Siliconbond.


NHBC Standards effectivefrom January 2000 qualifythat where a meter box isnot protected by a roof at anappropriate level, a DPCtray should be provided. See6.1 - S4 (e). The new BritishStandard 5628-3:2005stipulates cavity wall designshould be based on theassumption that waterpenetrates the outer leaf ofthe wall, even if it isrendered. (5.5.7.1)

technicalobservationsAccommodates numerouscavity sizes.Suitable for traditional buildand timber-frameconstruction.Unrestricted cavitycompartment area does notencourage mortar bridging.Self-supporting.Eliminates necessity to lineup inner and outer supportcourses.Branded with name andlogo as proof of type andaccompanying warranty.

Standard Type M, with protectiveexternal lip finish.

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Type P Cavitray for parapet walls

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problemHow to weatherproof parapet

walls.

introductionThe function of a parapet wall

cavitray differs from that of a

conventional tray, because both

skins of a cavity parapet are

outer skins, and accordingly

accept moisture. The purpose of

any parapet DPC is to prevent

rainwater travelling down the

exposed inside skin, which

becomes an internal wall below

the roof level. The preformed

Type P cavitray is designed to

overcome this problem.

solutionThe Type P cavitray is a rigid

horizontal DPC, manufactured

in long lengths. Preformed

angles enable the complete

installation of a parapet damp

course to be carefully planned

and controlled. It is self-

supporting and requires

building-in to one skin only.

Accordingly, the structural

stability of the parapet is

enhanced when compared with

parapet standard details and

related problems.

Water originating from the skin

adjacent to the roof is directed

to coverage with water

penetrating the building’s outer

skin where it gravitates in the

normal manner. Type W

caviweeps/vents may be

deployed to aid evacuation and

ventilation as appropriate.

Functionality is not hindered by

the direction of the wind. The

likelihood of interstitial

condensation, common to many

parapets, is thus reduced.

Such a preformed damp

coursing method is not

possible with traditional lead,

felt or polymer materials, which

sag, being soft and

unsupported across the cavity.

These materials are forced to

adopt a diagonal line in

crossing the cavity, with the

upper and lower edges secured

within the mortar beds.

sizes2400mm x 25mm lip x

110mm x 150mm cavity drop

Angles 450mm x 450mm

material2mm securtex finished

tensioned polypropylene

colourBlack

installation/site workProduct should be built into

masonry observing usual

requirements of laying damp

course. Incorporate lead

flashing to inboard side.

Full instructions accompany all

supplies.

bill of quantity wordingType P cavitray from Cavity

Trays of Yeovil, Somerset. BA22

8HU (01935) 474769.

Lay preformed Type P parapet

cavitray lengths and angles

within appropriate mortar bed

as work proceeds. Glove lap

and seal adjoining lengths.

Incorporate roof lead flashing to

detail. Observe accompanying

fitting instructions at all times.

Metres run including overlaps

=............ No of angles =.............


details..

related products andapplicationsFor parapet closer and DPC

support, see Type J.

• DPC integrity regardless of wind direction

• Enhanced parapet structural stability

• Takes up cavity variances


36

Type P Cavitrayshown herewith Type Junder coping.


The Type P was originallysubjected to much criticismbecause it promoted thecrossing of the cavityoutwardly rather thaninwardly. Tests indicated theoutward stepping profile wassafer - and eliminated thepossibility of water trackingon the underside of theprofile. It is interesting tonote that the outward profileis now the only parapetprofile featured withinBS8215:1991. Furthermore,BS5628-3:2005 within5.5.7.10 states: “it should benoted that the DPC orcavity tray structurallyseparates the parapet fromthe wall beneath, and thecoping from the parapet.Structural stability of theparapet should beconsidered in accordancewith 18.4.1.” This reasoningunderlines our tensionedprofile, which stepsoutwardly yet enhancesparapet structural stabilityas the external leaf is notinterrupted. Parapetsnormally have a stress factorof less than 0.1N/mm2.

technicalobservationsAll dimensions, includingcavity size suitability, can bealtered to suit a client’srequirements. Eliminatesdanger of underside watertracking associated with up-turned profiles.Branded with name andlogo as proof of type andaccompanying warranty.

Type P cavitray provides a clearunobstructed cavity compartment. The crossing of the cavity outwardlyovercomes a common problem. (See Designers’ comments.)

1. 90° Internal angle2. 90° External angle3. 90° Internal angle

The previous British Standard designstepped inwardly and created astructural weakness in the masonry.Cracking and staining occurred andwater untracked the inward step.

Cavity

100mm

50mm

110mm

Type P profile

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Type PWRBParty Wall

Rising Barrier

phone01935 474769 fax


cavitytrays.co.uk

• Provides barrier in party wall against adjacent propertywater contamination

• Acts as dpc at base of wall

• Acts as radon & methane barrier within party wall

• Provides NHBC preventative provision between dwellings

• Permits interfacing with perimeter wall gas barriers

37

The Type PWRB is able to interface radon andmethane cavity barriers andmaintain an unobstructedwater evacuation route.

problemHow to provide a more

effective and easier to create

barrier to prevent water

passing from one dwelling to

another via the separating wall

as depicted in the NHBC

guidelines. How to establish a

workable arrangement when

radon / methane barriers are

present in the external walls

and their presence prevents

water discharging from the

NHBC party wall channel

arrangement.

introductionNHBC section 6.6 (external

timber framed walls chapter)

provides guidance under

6.2(d) on how a party wall

should incorporate measures

to prevent water that

accidentally spills or floods

within one dwelling from

permeating an adjoining

dwelling.

Unfortunately such a shallow

channel can be easily

breached and/or filled with

debris during the course of

construction and is only able

to accommodate a small

volume of water (even if the

concrete under is channelled /

cast with a fall). Importantly, if

the property has radon or

methane barriers in its

external cavity walls, the inner

leaf section of those barriers

commonly terminate at a

higher level than that of the

party wall channel. With the

barrier in the way, water from

the channel has nowhere to

discharge.

solutionThe Type PWRB Rising Party

Wall Barrier acts as a dpc

and extends under both skins

of the party wall. The upstand

acts as a dam against water

flooding within one dwelling

from contaminating the

adjoining dwelling and its

upstand is capable of

controlling a far greater

volume of water than a

channel. Because its

functionality is achieved by

rising in the cavity rather than

descending (as with a

channel), it can interface with

the levels at which commonly

used perimeter gas barriers

are installed. Water can safely

evacuate and gastight integrity

can be maintained. The Type

PWRB can also be supplied

with bonded insulation to one

or both faces (See Designers

Comments).

sizes2400mm x 500mm x 150mm

All dimensions can be varied

to suit specific requirements

materialPetheleyne.

colourBlack.

bill of quantitywordingType PWRB Party Wall Rising

Barrier by Cavity Trays of

Yeovil, Somerset. BS22 8HU.

(01935 474769). Profile

dimension to suit party wall

measurements.. Incorporate at

level shown following

manufacturers instructions.

related products andapplicationsSee GBPWIS for

dpc/shuttering/insulation

product for party walls.

See Type PWIB for combined

vertical dpc and fire barrier.


Variations of the TypePWRB with (non water-absorbing) insulationbonded to the rising sectionare available. When suchinsulated versions areinstalled, any party wallinsulation presentcommences from thebarrier top rather than fromfloor level. Thus it begins ata level that is clear of waterwash typically experiencedwhen flooding originateswithin a dwelling. Thisoption minimises waterretention following anincident and can aid latentcost reduction. Creating achannel within a cavity partyis time consuming and thedepth to which any channelcan be formed is limited.Providing protectionupwardly is the less costlyroute, and has theadvantage that if gasbarriers are present in theexternal walls, theevacuation route of anywash of water is notobstructed.

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Type Q ArrestingBarriers

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problemHow to create DPC barriers

to arrest water-wash within

cavity walls to specific areas

or features.

introductionType Q arresting barriers is

the term applied to water-

controlling DPC projections

within cavity walls. The

function of these barriers is to

invisibly arrest and reduce

water-wash from an area of

cavity wall above a given

feature or construction detail.

Masonry below the barrier

level however still remains

damp and receptive to rain

penetration. The purpose of

the barriers is to influence

control of water volumes

within a wall and minimise

damp transmission risk.

solutionType Q Arresting Barriers are

manufactured in long lengths

from semi-rigid solid DPC

polypropylene. Numerous

profiles are available and

preformed angles, stopends

etc., permit long lengths to be

quickly and economically

incorporated to service

specific masonry areas.

A common use is to protect

the top of full-fill cavity

insulation. The NHBC

Standards Manual stipulates

an appropriate DPC must be

incorporated at the highest

insulation level, whenever

insulation fully fills a cavity but

does not terminate at the top

of the wall. The barrier

achieves this, preventing a

wash of water at this

vulnerable termination junction.

The arrested water is

discharged out of the building

fabric via Type W weepvents

that also promote the cavity

wall to breathe. Arresting

barriers differ from

conventional cavitrays and

DPCs as the base dimension

is commonly narrower than

the full width of the

external skin.

sizes2400mm standard overall

length. Base dimension

approximately 75mm.

Upstand dimension 150mm

minimum. Preformed internal

and external angles 450mm x

450mm.

Arresting barriers can be

supplied in almost any special

size with dimensions to suit

client’s particular needs.

Adjoining lengths glove-lap

and Siliconbond to make up

runs. Please state cavity width

being used.

The tensioned design of the

cavity upstand eliminates the

need to build barriers into the

inside skin.

material1.5mm tensioned solid

polypropylene DPC securtex

textured finish.

colourBlack.

installation/site workType Q arresting barriers

should be bedded within the

horizontal mortar joint at the

appropriate course level.

The cavity upstand should be

adjusted where required to

suit the cavity width in

question. Preformed lengths

and angles should be glove-

lapped 150mm minimum to

form waterproof joints aided

with Siliconbond seal

sandwiched between overlays.

bill of quantitywordingType Q arresting barriers

from Cavity Trays Ltd of Yeovil,

Somerset BA22 8HU (01935

474769). Bed preformed

barrier within horizontal mortar

joint at the appropriate course

level as work proceeds. Do not

dry bed. Lengths and angles

to be glove-lapped to provide

a minimum of 150mm lap.

All overlays to incorporate

Siliconbond seal. Ensure tray

and all bricks are correctly

bedded at all times.

Incorporate Type W

weepvents in masonry perp

joints within the external skin,

every fourth brick. Incorporate




details.

related products andapplicationsSee Type G for horizontal

cavitrays, and Type W, Euro,

beak and small adjustable for

weeps. See cavibarriers for

firestops over which this

product may be used.


• Accommodates cavity widths variance

• Rigid profile eliminates sagging or misplacement

• Clear cavity compartment area

38

The Type Q has a narrow basedimension and differs from aconventional horizontal cavitray. Ina rendered wall a special widerversion must be used.


The masonry above thebarrier and below thebarrier is susceptible to rainpenetration. The purpose ofarresting the water is toprovide primary orsecondary protection to aspecific construction detail.In the case of the renderedwall, it is recommended thebase dimension matchesthe masonry thickness.Uneven moisture-inducedsize changes aroundfeatures within the substratecan induce cracks in render.Use of arresting barriersand the evacuation of waterarrested by barriers alsopromotes equilibrium.Observe BS 5262. Consideruse to comply with controlmeasures applicable 12metres from base of cavitywhen building is 12 to 25metres in height, and at 7metre intervals thereafter.

technicalobservationsPreformed profiles ensurecorrect barrier shape andperformance.All dimensions includingcavity size suitability, can bealtered to suit client’srequirements.Unobstructed cavity traycompartment area.Cannot sag, tear or buckleand does not rely on sitefabrication.Branded with name andlogo as proof of type andaccompanying warranty.

Protectingfeature wherecavity reduces.This particulardetail can alsobe protectedusing a DropCloak. SeeType CD.

Protecting topof insulation

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Type R Cavitray cavity closer/water-check tray

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phone01935 474769 fax


cavitytrays.co.uk

problemHow to close cavities whilst

introducing a water-check.

introductionWhen intermediate upper

floors of concrete are cast

in situ and extend through to

the exterior face of a building,

two problems are

immediately apparent:

1 A requirement of

sealing/closing over the cavity

is necessary to prevent the

concrete spilling into the cavity.

2 The method of closure

must incorporate a water-

check to the underside of the

concrete, to prevent water

penetration below the floor

slab. This detail is often

overlooked, but there is the

possibility of settlement and

thermal movement causing

cracking at this important

junction between concrete

and masonry.

solutionThe Type R cavitray

overcomes such problems.

Preformed and robust, the

Type R cavitray quickly and

economically closes the

cavity, whilst preformed

angles accommodate corners

and changes in direction. The

Type R cavitray becomes an

enveloped item of shuttering,

which provides an upturned

V-shape water-check that

prevents the tracking of

dampness across the cavity.

The upturned profile (rather

than the down-turned profile)

is not susceptible to

accommodating coarse

aggregate during the pouring

of concrete, which might

encourage capillary action if

air voids are present and

permit penetration pooling.

sizesTwo standard sizes are now

available, in standard lengths

of 2400mm.

Type R size 1 = 2400mm x

135mm overall width with V

section of 25mm x 25mm x

25mm. Type R size 2 =

2400mm x 160mm overall

width with V section of 35mm x

35mm x 50mm approximately.

materialStandard 1.5mm solid

polypropylene DPC Securtex

top textured finish.

Also available in austenitic

stainless steel.

colourBlack in polypropylene or

natural steel finish in

stainless steel format.

installation/site workSpot bed both skins of cavity

wall and place Type R cavitrays

in position. Adjoining lengths

and angles glove-lap 200mm

minimum. Ensure firm

location and allow to set.

bill of quantitywordingType R cavity closure/water-

check tray from Cavity Trays

of Yeovil, Somerset BA22

8HU (01935 474769).

State size required, R1 or R2.

Spot bed both skins of cavity

wall and place Type R cavitray

in position. Glove-lap all

lengths and angles a

minimum of 200mm.

Ensure all installation is

strictly in accordance with


Total measured run including

laps =....... Request


upon completion.


details.

related products andapplicationsThe Type R cavity closer/

water-check tray may be used

with the Type G cavitray

which provides the horizontal

DPC above slab level. Cavity

ventilation via perps to address

interstitial condensation may

be achieved by incorporating

weepvents in the perps of the

course immediately below the

Type R, at 450mm centres.

See Type W which is

recommended for such

purposes.

• Integral shuttering formwork and closer

• Introduces water-check

• Lengths and angles for immediate installation

• Promotes consistent build detail

39

Type R shown belowfloor/ceiling slab. Preformed tray shownabove slab.


Consideration should begiven to a full soft joint tothe bottom of cast in situconcrete floors that areintegral with the storeyheight of the frame. Thus provision for expansionis introduced betweenmasonry head andunderside of the concrete -see Siliconbond.Masonry built off theconcrete should alwaysincorporate an appropriateDPC cavitray with stopendsagainst full depth columns -see Type G.

technicalobservationsDual function productacting as water-check andalso integral shutteringtray.Upturned profileeliminates dangers ofcapillary action andpooling of water withinprofile.Fast installation withglove-laps to all adjoiningsections.Puncture-proof, robust andpreformed.Branded with name andlogo as proof of type andaccompanying warranty.

Laid in this manner, pooling of penetrating rain might occur.

Recommended use which eliminates risk.

Slab edge usually waterproofed withexternal finish or feature to preventdamp penetration through concrete(omitted for clarity).

Standardangle

Standard profile

55mm 25mm 55mm

Rain Screen Bafflesand Flashings

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problemHow to provide rain

penetration control and

drainage within rain screen

and panel clad constructions.

introductionIn open rain screens and

pressure-equalised rain

screens (PER), dependence is

placed on the ‘screen’ layer

deflecting the kinetic force of

the driving rain. Rain screens

can minimise the building

wetting forces including

capillary behaviour and wind

pressure differences. Preformed

rain screen flashings and

baffles are necessary to arrest

water that penetrates between

and gravitates behind the

screen face.

solutionRain screen baffles and

flashings are specifically

profiled to suit individual

applications. They are

proportioned to protect the

rain screen where there are

intentional openings. Examples

include vents, vertical and

horizontal slit junctions and

eyebrow apertures between

panels. Baffles and flashings

are incorporated so they arrest

and immediately evacuate

water from the

compartmented screen

section. In the case of

horizontal rain screen

flashings, these are secured to

the inner face and moulded

with an incline predisposed to

drain water out of the

structure. Where baffles and

flashings are secured in a

vertical application, it is

commonplace for the profiles

to splay between 120° and

150° rather than project at a

90°angle, which is less

tolerant to imbalanced air

movement within the vertical

compartments.

sizesProfiles supplied on a bespoke

basis. There are generally no

limitations to sizes within all

popular constructions. Please

see examples illustrated. Upon

receipt of drawings we will be

pleased to advise you what is

recommended for your project.

materialPetheleyne.

colourBlack.

installation/site workRain Screen Baffles should be

incorporated at the




of BS5628 and Robust

Details.

Build into inside skin or secure

against inside skin as per

instructions that accompany

all consignments.

bill of quantitywordingBespoke flashings and baffles

for curtain walls/panel clad

walls by Cavity Trays of Yeovil,

Somerset. BA22 8HU.

(01935 474769). Schedule

provided by Cavity Trays Ltd.

ordering/regulationsSee inside back cover.

related products andapplicationsSee also arresting barriers and

Type G cavitrays for damp

protection.

See cavicloaks for traditional

cavity wall damp control.

See Type CFIS for cavity

barriers/fire stops/

compartmenting.

See Type PWIB for combined

DPC and fire barrier/

compartmenting.

• Control of penetrating water

• Pressure equalised and open screen formats

• Petheleyne sections

• Available in all dimensions

• Use with SAF NHBC - compartmentation

40


The principle of curtainwalling/open panel claddingis similar to that witnessedwhere a fly cover standsabove a tent – effectivelypreventing rain from reachingthe lower canvas thatremains dry. When the off-standing external screen issimilar to the external skin ofa cavity wall, the use ofconventional cavitrays mightbe appropriate. However, ifthe external screen consistsof non-butting panels, or isperforated by open joints,slots or ventilation apertures,(necessary to meet the (PER)pressure-equalisationrequirements of an exposedstructure), one has theaccompanying obligation toaddress localised wateringress that can be moresevere. Additionally, whereasmoisture-laden air can rapidlybe expelled via repetitiveventilation apertures withincurtain walling, these alsorequire adequate flashingsand baffles to provideeffective control ofpenetrating water.

technicalobservationsThe thermal loss viapolypropylene flashings andbaffles is minimal. Thustheir use can be employedto good effect to controlwater paths and maximisepotential comparative heatretention.

The lower end of each vertical cavitybaffle terminates above eachhorizontal at an angle to match thehorizontal profile whilst maintaining afree air space to promote pressureequalisation.

41

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Type TST threshold and sill overlay tray

phone01935 474769 fax


cavitytrays.co.uk

problem How to protect against damp

and water penetration around

sills and thresholds.

introduction Many styles of external sill

and threshold are more

effectively and reliably damp-

proofed using a preformed

threshold overlay tray. In the

case of sliding patio door

thresholds, the relatively low

sill and position often prevent

an effective DPC

arrangement using

conventional roll damp course.

There is no natural vertical

barrier break at the base of

the opening and a low profile

construction detail is

susceptible to water ingress

through seepage and capillary

action accompanied by

thermal pumping.

This manifests in dampness

spreading inwardly, at the

junctions where the oversite

membrane emerges.

In other instances, the foot

traffic into and out of the

doorway during the course of

construction can damage any

damp-proofing membrane in

the vicinity. A preformed

threshold overlay tray is

available to provide a

standardised solution to this

problem. It is known as the

Type TST.

solutionThe threshold and sill overlay

tray is a three-sided moulded

unit that is positioned on the

oversite prior to the laying of

the screed (and optional

insulation). The purpose of the

Type TST is to provide

additional DPC to isolate the

damp external masonry leaf

and the opening reveals, from

connection with the floor

screed. The upstands ensure

penetrating water cannot

transmit inwardly.

The base of the Type TST

extends the full width of the

opening and into the building

to a maximum of 485mm.

It is enveloped under the

screed and is an effective

extension of the oversite

membrane.

The moulded Type TST

overcomes localised DPC

misplacement or distortion,

which can be problematic

with conventional materials.

Site build quality is controlled.

Underneath the screed and

hidden from view, the correct

and intended waterproof

detail is incorporated, rather

than the hoped-for detail.

sizes State structural opening.

Available in all standard

opening widths.

Upstands 115mm.

The 175mm reveal return

may be trimmed on site.

Base depth 485mm.

Other styles available

materialPetheleyne solid DPC.

colour Black.

installation/site workLocate and bed in position.

Ensure all upstands are

against intended surfaces and

upright. Ensure continuity of

protection is maintained with

oversite membrane. Proceed

with laying of screed. Full

installation instructions

accompany the Type TST and

should be studied prior to

commencing work.

bill of quantitywordingType TST threshold and sill

overlay tray from Cavity Trays

of Yeovil, Somerset, BA22

8HU (01935 474769)

Incorporate on oversite at

thresholds, prior to laying of

screed. Total number.........


details.

related products andapplicationsSee Type LTT for level and

stepped threshold damp

protection.

• Standardised ready-shaped solution for openings

• Ensures continuity of oversite membrane protection

• Not susceptible to misplacement or damage


Getting the detail right toensure door thresholds incavity walls are perfectlydamp-proofed, should intheory be straightforward.However, textbook methodsdo not take into accountdamage that occurs tomembranes left protrudingon busy sites -especially atdoor openings and inparticular where the verticalelement intersects. If torn orintermittent, dampness canpermeate. The originalBRE investigation oftraditional housing totalled955 faults. 11th in the list wasmissing/faulty dampcourses to door sills andthresholds giving rise towater penetration. Placing athreshold overlay tray justprior to screed laying, to complement the originalmembrane/damp-course,can re-establish the detaildemanded. It is a precautionnow commonly used bymany leading housebuilders. It is a cost-effective way of ensuringsite quality, within an areathat can be costly anddisruptive to rectify oncework has been completed.

Type TST used with popular two-leaf patio doors. The structural width is variable.

Use of the type TSTestablishes damp-proofing integrity at themeeting point betweenover site membrane,vertical closer, revealmasonry, thresholdmasonry and sill. Over64% of reported dampproblems at low level inopenings were as a resultof lack of continuity ofprotection measures.

42

Type U Cavitray for undersills

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problemHow to protect masonry sills

against damp penetration.

introductionThe formation of a brick or

tile sill is easily accomplished

with the use of a Type U

undersill tray. Trays are

supplied in a variety of

profiles to suit the shape of

sill required. Once bedded in

position, the bricklayer has

automatically established an

undersill DPC. The sill bricks

or tiles can then be laid using

the profiled tray as integral

guide shuttering.

solutionThe Type U cavitray is a

preformed DPC unit.

It is profiled to also form

integral shuttering to receive

sills constructed of masonry

or tile.

The Type U cavitray is

enveloped within the building

structure providing the ideal

purpose-shaped DPC. An

upturned external edge lip is

supplied to the front of the

Type U cavitray. This acts as a

guide to provide accurate tile

or brick sill alignment.

The entire front section of the

Type U which projects

forward of the masonry line,

is fully detachable. An integral

separating link, permits this

front portion of the tray to be

removed, once the mortar

has cured. The front bedding

area of the Type U undersill

cavitray which is incorporated

within the external skin

features apertures which aid

positioning and permit transit

drainage.

insulation optionType U undersill trays are

now available with an

optional 25mm polystyrene

insulation barrier, bonded to

the vertical upstand (subject

to sill design or space

permitting). Specify clearly if

this option is required.

designconsiderationsThe Type U undersill cavitray

may be used with timber-

frame build and traditional

build construction.

The extent of differential

movement is usually more

pronounced with timber-

frame and allowance is

required for the direction of

shrinkage, as per NHBC

Performance Standards. This

is easily accomplished using

the Type U undersill cavitray.

An expansion gap should be

pointed in with Siliconbond to

provide a weatherproof detail.

See NHBC Design

Performance Standards, 6.2

D6(c). (An expansion gap is

applicable to all forms of

construction but when

timber-frames are employed

the movement factor is

normally greater.) At all times

the designer should ensure

that the proposed sill design

is sufficient to create a strong

mass of construction in terms

of strength, proportions and

service.

sizesThe Type U is available in a

range of profiles. One may

select an appropriate profile

to suit the angle of sill

required and the material in

which the sill is to be formed.

Examples include brick, tile,

or stone in solid or module

form. Popular profiles are

illustrated and the extent of

variations available to suit

client’s specific needs is

extensive.

Our design department will

be pleased to advise upon

your requirements and

submit recommendations.

Patent restrictions often

dictate our undertakings and

we will advise the most

appropriate Type U style in

which your proposed sill

detail can be accommodated.

Maximum length 2400mm.

• Shaped DPC cavitray

• Integral sill alignment facility

• Removable front section

• Ensures consistent build detail

• Selection of profiles

• Traditional or timber-frame construction Type U in position.


BS5628 stipulates that allpervious or jointed sills orsub-sills should be providedwith a DPC for the fulllength and width of the sillbed. There is also asecondary requirement forthe DPC to be turned up atthe back and ends for thefull depth of the sill, where itis in contact with thebacking (internal skin). A brick sill subjected to a20°C temperature rise willexpand by 0.10-0.16mm/m(millimetres per metre).Such thermal movementoften results in smallfissures or fractures within asill mortar bonding joint. Thebenefit of the sill DPCarresting any rainwaterwhich enters the sill detail isparamount.Permits easy compliancewith NHBC 6.1 - S4(d) and6.2 - D4(a) (Moisturecontrol and insulation).Exposed site classification.The preformed rigid shapealso avoids the common siteproblem of misplacement ofconventional DPC material.

Variations to the profile and variationsto the material thickness can beaccommodated to suit the customer’srequirements.

65mm

110mm

40mm

103mm

48mm

55mm

The entire front section of the Type Uwhich projects forward of the masonryline is fully detachable. An integralseparating link permits this frontportion of the tray to be removed,once the mortar has cured.

The Type U ideally extends beyond thestructural opening. Always clearlystate the opening dimension and theoverall dimension.

150mmwindow opening

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Type U Cavitray for undersills

phone01935 474769 fax


cavitytrays.co.uk

Glove-lap to make up longer

lengths. Minimum 200mm.

Stopends for use with Type U

undersill cavitrays are supplied

separately to permit the

installer to incorporate them

on site in the most

appropriate position. If the sill

feature is of a greater width

than the opening dimensions,

specify sufficient tray length to

service this requirement.

type U undersill(alternative style)Type U undersill cavitrays are

also available for use with

solid concrete, reconstructed

and natural stone sills. In the

example shown, the Type U is

acting as an arresting barrier

whilst providing DPC integrity

between the pre-cast sill and

the internal skin. The DPC

has not been returned in the

bedding course immediately

under the sill, but instead is

terminated approximately

75mm lower. This approach

permits collected water to be

safely discharged via Type W

weepvents.

This profile promotes water

evacuation of the cavity and

breathing of the cavity void -

a benefit which is not

possible if the DPC is

returned at a higher level.

material2mm black polypropylene

with Securtex top surface

finish. Insulator typical

sampled thermal conductivity:

0.037.

colourBlack polypropylene.

installation/site workType U undersill cavitrays

should be handled and

bedded in position in the

same manner as

conventional DPCs and

lintels. Do not dry bed. Locate

undersill cavitray so that the

back vertical section (with or

without integral insulation)

always rises against the skin.

The front of the undersill

cavitray must be fully bedded

on mortar and soundly

bonded to the outside skin.

The rear of the tray must

similarly be fully bedded and

bonded to the inside skin.

Following firm location in the

correct position, traditional

construction of the sill in

masonry or tile may proceed.

Always solidly construct

using a suitable mortar.

Ensure stopends are in

position. The front lip should

function as a guide against

which the sill edge is aligned.

The front section of the Type

U undersill cavitray is

removable and the break-

joint should be positioned so

that it is slightly forward of

the faceline of the exterior

skin. It is recommended that

an expansion gap (6mm) is

left between the top of brick

or tile sill and the underside

of the frame sill. Seal at a

later date using Siliconbond.

Remove guide lip following

setting of mortar, if desired.

At all times observe the

recommendations of the

NHBC Performance

Standards.

In the case of rendered wall,

the undersill cavitray should

be of a size so that the

removable front section

break-line is forward of the

rendered face.


details.

related products andapplicationsFor venting below pre-cast

sills, see Type W weepvent,

Euroweep-vent and small

weepvent. See siliconbond

for flexible caulking which

may be applied to expansion

gap between window sill and

sub-sill.

• Shaped DPC cavitray

• Integral sill alignment facility

• Removable front section

• Ensures consistent build detail

• Selection of profiles


43

Type U with tiled sill.


Traditional construction with brick sill

Traditional construction, tile sill

Timber-frame construction, tile sill

Traditional construction, solid stonesill. Note the provision of caviweeps.

Expansion gap should always beleft between window sill and sub-sill. Siliconbond may be used at thispoint to provide a resilient yetflexible union.

Timber-frame construction withbrick sill

Pyramid Weep(Masonry Bleed Straw)

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problemHow to provide water

evacuation routes from

masonry where bedding

courses and perps are too

narrow to accommodate

conventional weeps. How to

evacuate water from ashlar

walling. How to evacuate

water from random rubble

and snecked rubble walling

without punctuating

appearance.

introductionPyramid Weeps provide

passive and discreet water

exit routes. When regularly

incorporated within the

bedding mortar, the bleeding

of water from the masonry is

possible with the minimum of

visual impact.

solutionManufactured in a material

that is durable to provide a

long service life, the Pyramid

Weep is a robust triangular

conduit. The shape permits it

to be incorporated within a

standard-sized mortar bed -

discreetly and unobtrusively.

Where the mortar bed and

perps are narrower than

usual, it is still possible to

incorporate the Pyramid

Weep by positioning its base

in the bedding course with its

converging point rising into

the perp joint. Thus the

Pyramid Weep is versatile in

a wide range of masonry and

mortar styles.

sizes 100mm x 8mm x 8mm x

8mm to suit standard

masonry skin 240mm x 8mm

x 8mm x 8mm to suit

masonry skins up to 240mm

Packs of 50 or 100.

(Easily cut on site if required).

materialPVC-U.

colourMortar grey.

installation/site workThe distance between weeps

can be varied to suit the

application. In servicing

evacuation from lintels, dpc's

and trays, positioning at 200-

250mm centres is normally

appropriate. Where a specific

masonry feature requires

drainage/bleeding, the

frequency may be varied

pending placement

opportunities. The Pyramid

Weep is normally finished

flush with the external face.

bill of quantitywordingPyramid Weep by Cavity

Trays of Yeovil Somerset

BA22 8HU. (01935 474769).

Incorporate to evacuate

arrested water from all dpc's,

trays and lintels and/or

masonry features @ ....mm

centres. Number............

ordering/regulationsSee inside back cover

• Bleed outlets promote continuous water drainage

• Discreet & passive when installed

• Fits within narrow bed joints and perps

• Permits water evacuation from bespoke masonry features


To prevent mortarcontamination & blocking,some masons preferinstalling the longer PyramidWeep so it protrudes duringconstruction.The excess is then cut offwhen the mortar is set. (Thisfollows the custom whenstraw reed was used tobleed walls and theprotruding reed was cutback once the wall had beencompleted). 'Letting the wallbleed' with masonry bleedstraws was the forerunnerto today's cavity wall weep.Selected straw reed(commonly Devon reed)was cut and dried andenveloped within the mortarbeds of masonry walls.Straw reed provideda reasonably proportionedconduit through whichmoisture and water couldflow. Reed straws relied onfree-flow and capillarybehaviour.Unfortunately reed breaksdown and degrades over aperiod and subsequentlyflow was reduced orrestricted. Lime mortar wasdiscovered to sometimesleech and sludge the reedends. The dimensions of thePyramid weep maximiseflow within a compactconduit that will not breakdown or degrade.

The triangular shape offers greater strength. Water and mortar debris wash is along a flat basethat does not restrict and comfortably beds in thelowest possible position for optimum evacuation.

44

problemTo evacuate water from lintels

and cavity trays.

introductionThe beak weep provides an

alternative way of releasing

penetrating water from lintels

and cavity trays installed

within a cavity wall. The beak

weep matches the height of a

standard perp joint, but has a

reduced front section shaped

to be almost indistinguishable

from the mortar joint.

solutionThe base flow path of the

beak weep is direct, and does

not taper, permitting arrested

water and debris to freely

evacuate. The discharge

outlet is underneath the beak,

so water and debris is not

prevented from discharging

under conditions of directly

blowing wind. Accordingly, a

grille does not feature on the

beak weep, as there is no

place visible on the beak

front for insects to enter.

Each beak is moulded in a

polished clear polymer,

enabling it to blend in with

any colour of mortar or

masonry.

Beak weeps are for water

discharge only, and should not

be confused with our dual-

purpose combined weeps and

vents that have a higher

discharge capability. We

recommend a greater number

of beak weeps be incorporated

to compensate and provide

multi-outlet opportunities

(450mm centres, see

installation). If an almost

undetectable appearance is

required, the beak weep

combines functionality in an

aesthetically neutral naturally

blending style.

extension ductA weep extension duct is

available to attach to extend

the beak weep. The duct

permits the weep to be used

in masonry of a depth of up

to 300mm. For intermediate

masonry dimensions the duct

can be cut to suit.

sizes65mm x 108mm.

62mm x 200mm plus

connection flange.

materialBS polypropylene.

colourNatural clear polished.

installation/site workPosition in perp on DPC,

lintel or cavitray in

accordance with our

instructions. Spacing at

450mm centres in

accordance with NHBC and

BRE recommendations.

bill of quantitywordingBeak weep by Cavity Trays of

Yeovil, Somerset, BA22 8HU.

(01935 474769). Build into

perp joints over lintels, trays

and DPCs at 450mm

centres. Number ........


details.


The drop outlet does notencourage build-up ofmortar (initial) debris wash,a common occurrence ifthe apertures are on thefront and below certainminimum dimensions. (Seeother entries in which werefer to minimum sizes wehave established in tests tobe functionally serviceable.)The mid sweep of the beakpermits mortar infill withoutadverse forward slump.


The front of themeniscus shapedBeak Weep istranslucent to blendwith mortar andmasonry.

9mm

65m

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108mm

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Beak Weepphone

01935 474769 fax01935 428223 em

[email protected]

• Discreet unobtrusive appearance

• Protected against direct wind entry

• Insect resistant

• Direct uniform evacuation path

Beak weep used with extension duct to providedrainage evacuation route up to 300mm maximum.

45

Small Weepvent hidden appearance, adjustable size

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• Discreet appearance

• Telescopic - adjusts to suit masonry thickness

• Clear throughout - does not bottleneck

• Protective cap keeps outlet clean during installation

• May be used within rendered surfaces

problemTo weep via a perp joint, thus

promoting water evacuation

from DPC, lintel or cavitray

whilst permitting the cavity to

breathe.

introductionThe small weepvent provides

an alternative way of

establishing a water exit route

from a cavity wall. This product

incorporates features which

benefit the user/installer

which are not matched by any

other product or system.

solutionThe adjustable ‘hidden’ small

weepvent differs from other

weeps with reduced outlets.

The performance of any weep

is dictated to a great extent

by the actual dimensions and

shape of the discharge outlet.

If the outlet is too small, it is

susceptible to blocking by

mortar debris. However, if the

outlet is too big and

unprotected, it might act as

an open ‘hole’ through which

wind-driven rain can blow,

thus preventing the weep

from functioning. The small

weepvent overcomes these

problems and offers a

considerable number of

accompanying advantages.

The front of the small

weepvent is practically

undetectable when built into

the perp joint. The ‘hidden’

outlet consists of a

rectangular insect-resistant

grille with angled mouldings.

The outlet dimensions offer a

higher throughput than other

small models, - in instances in

excess of 100% because the

small weepvent does not

bottleneck in shape but

maintains relatively consistent

dimensions, mortar debris can

wash through and discharge

without clogging. Water

follows a direct and

unobstructed route.

The small weepvent is also

telescopic. There is no need to

purchase extension sleeves to

accommodate external skins

built of different thicknesses.

Similarly, the rendered wall is

instantly and correctly

accommodated.

The telescopic facility means

the small weepvent always

fits and always suits. This

compatibility feature is of

considerable benefit to the

contractor. It also aids the

merchant as one model fulfils

all popular construction

requirements. A further

important benefit of the small

weepvent is the front

protective cap. Following

building-in it is removed

revealing a clean and mortar-

free outlet grille. This simple

facility ensures cleanliness -

an important consideration

especially when rendering

walls. This telescopic feature

may also be employed to

project the small weepvent

forward of the face-line when

rendering, and pushed back to

the faceline upon completion.

Wind-driven rain deflection is

maximised because the grille

is set forward. This position

also prevents insect fostering

within body of weep vent.

sizes93mm x 24mm x 9.5mm,

with telescopic section

providing additional 70mm

maximum.

materialBS Polypropylene or BS ABS.

colourBeige, grey, terracotta or clear.

The standard colour of

mortarblend beige harmonizes

with most masonry styles.

Installation/site workPosition within perp joint in

accordance with our

instructions and the


NHBC/BRE (normally at

450mm centres with a

minimum of 2 number per

lintel). Employ telescopic

facility to suit thickness of

outer skin. Following

installation, remove protective

external cap. Ensure units

are clean.

bill of quantitywordingSmall weepvent (with hidden

appearance and adjustable

size) from Cavity Trays of


(01935 474769). Introduce

small weepvents into perp

joints to facilitate discharge of

water from all cavity trays,

lintels or similar. (Stipulate

weepvent centre/frequency.)

Total number=.... Request


upon completion.


details.


The horizontal shape of thesmall weepvent avoidsfunnelling - a situation inwhich mortar debris of agiven size might wash intothe back of a weep andbecome lodged because thedimensions reduce andtaper. The small weep ventdoes not bottleneck inshape. The water exit routeis designed to be direct toproduce non-clog behaviour.NHBC Standards extra(12/4/96) refers to the useof weeps and the smallweepvent may be employedto satisfy such requirements.When calculating the freeexit dimensions as apercentage of the openingsize dimensions, a yield of84 percent produced thehighest figure currentlyavailable in a product of this type.

technicalobservationsHigh throughput.Insert resistant grille.Protective cap promotescleanliness.Telescopic feature ensurescompatibility.Suitable for use withrendered walls, also varyingthicknesses etc.Branded with name andlogo as proof of type andaccompanying warranty.

This shows acommon DPC

and rendercompromise.

If weep provision isignored, in the long term

the render coat freezes. Spalling isthe consequence. A water escape

route is essential and can alleviate this. The small adjustable weep provides such an

escape. Ideally above a window or door opening theDPC should always project under a bellcast head.

The removable protective front flap keeps the small weepvent clean of mortar when building-in.

93mmExtends a further70mm max.

Height 24mm x 9.5mm

46

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Type W CavitrayWeepvent

phone01935 474769 fax


cavitytrays.co.uk

• Dual-function combined weep and ventilator

• Insect resistant grille

• Integral water-check baffles

• Superior air throughout and water discharge capability

• Optional render protection cover, keeps grille clean during installation

• Satisfies timber frame construction ventilation of compartmenting

47

Type W Cavity Weepvent.


The absence of absorptionmaterial in the Type Weliminates the danger of‘trapped or held’ waterfreezing in extreme weatherconditions and spalling ofthe masonry taking place.(Test ASA/1990). The TypeW should not be confusedwith single-function systemswhich do not offer thebenefit of bi-pressureextraction and performance.The NHBC StandardsExtra Issue 21, 2001,Illustrated the Type W withits integral grille, statingpreformed models arepreferable to open perps,as grilles prevent entry ofinsects into the structureand weeps that do nottaper are less likely toblock. The Type W may beused to satisfy NHBC 6.2- S7: Cavity wall should bevented where walls aredivided by barriers at highand low levels. NHBCstipulates the equivalentairflow of an open perpevery 1500mm. Positioningevery third or fourth brickcan fulfil requirement andprevent insect infestation.


problemHow to provide outlet drain to

discharge water from

tray/DPC. Also ventilator as

required to ventilate wall

cavities, insulated cavities and

suspended floor situations.

introductionCavity walls require perp

weeps to evacuate water from

trays and lintels. Cavity walls

also require perp vents to

remove moisture-laden air.

Both functions can be

accommodated with a

weepvent that offers many

benefits.

solutionThe type W weepvent is the

first specifically conceived

dual-purpose weep and vent.

Aesthetically and practically

designed with a functionally

inclined front, the Type W is

finished with an insect-

resistant grille. Air can easily

enter the grille which, by virtue

of its shape, provides a

superior overall air intake area.

Internal baffles control any

water which may enter and

encourage discharge via the

weep outlet on the projecting

underside of the Type W.

The Type W removes the risk

experienced with open-ended

weeps and vents - often an

overlooked but important

factor on exposed high-rise

buildings. Used as a ventilator,

the Type W ensures superior

performance, and allows the

wall to breathe.

Used as a weep, the Type W

encourages correct water

discharge, as the design

makes use of positive and

negative air pressures. Wind-

driven rain deflection is




within the body of weep vent.

the type Wextension ductThe extension duct is designed

to push-fit onto the Type W, to

form a 305mm straight-

through ventilator and weep.

protection whenbuilding-in An optional front cover is

available to ensure cleanliness

when incorporating in

rendered work. Covers are

florescent and coloured for

obvious identification. They

are easily removed upon

completion of render work.

sizesStandard size 105/115mm x

65mm x 10mm plus lockfit

wedges. Extension duct

200/225mm x 65mm x

10mm. Overall combined

length 305mm. Standard Type

W provides 320mm2 free air

space.


colour Available in colours to

harmonize with popular

mortar shades: Grey, black,

beige, brown, terracotta, white,

clear. Special colours and

shades available.

bill of quantitywordingDual purpose Type W

weepvents from Cavity Trays


8HU (01935 474769).

Colour = ..... Introduce Type W

units into perp joints to

facilitate discharge of water

from all discharge cavitrays

and all lintels. Observe

spacing recommendations.

Total number = .....

Alternative: Install extended

version Type W weepvents

(basic unit plus extension

duct) to every third/fourth

perp joint in positions

indicated.





details.Basic Type W acts as a ventilator.Functionally inclined grille ensuressuperior performance.

Basic Type W acts as a weep,discharging water from cavitrays,DPCs, lintels, etc.

Extension duct + Type W. Use as amajor weep. Extension ducts canbe increased or reduced toaccommodate non-standard wallthickness applications.

The Type W can be extended to form a major weep/major vent,with the addition of an extension duct.

200mm105mm

115mm

62m

m

Euroweep-vent alternative perp/weep ventilator

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[email protected]

• Dual-function weep and ventilator

• Integral baffle

• Vertical front

• Reduced size without bottleneck exit route

problemHow to discharge water from

DPCs and cavitrays.

An alternative product is now

available offering smaller

overall dimensions but with

high performance

categorisation.

introductionEuroweep-vents are positioned

within the perp joints between

masonry. Their function is

twofold. They act as a weep to

discharge water from DPCs,

cavitrays and lintels. They also

act as ventilators to encourage

the cavity to breathe.

Euroweep-vents were

developed and are now

extensively used on the

continent. They can also satisfy

UK, NHBC and Building

Regulation requirements.

solutionThe compact Euroweep-vent

can be accommodated within

perp joints even when the

external skin is constructed

of masonry units of minimal

height. They are therefore

suitable for use within a

wider range of walling styles

currently used in Europe.

Compact size does not

compromise the performance

of the Euroweep-vent which

promotes excellent free air

flow and discharge behaviour.

The Euroweep-vent performs

efficiently and being available

in several colours, means it

merges and harmonizes with

masonry within which it is

incorporated. Euroweep-vents

may be used as weeps to

discharge water. They may

also be used as vents (at high

and low level) to address the

NHBC and Zurich

Insurances directives.

Euroweep-vents have full

height baffle protected water

discharge routes and are not

susceptible to blocking.

We recommend one

Euroweep-vent minimum per

900mm of masonry for

venting and weep purposes.

Lintels, cavitrays and damp

courses generally require a

minimum of two Euroweep-

vents although the number

should be increased on long

installations.

Wind-driven rain deflection is




within body of weep/vent.

designconsiderationsWhen cavities are not

continuous but are contained

between cavity barriers, studs

or frames, there is a

requirement to ventilate each

individual cavity and BS5250

demands the equivalent of an

open perp end every 1.5

metres. However, the British

Standards also draws

attention to the accompanying

need to protect against the

ingress of large insects and

rain penetration.

sizes49mm x 87mm x 9mm.

Free airflow approximately

300mm2 per unit.


colourGrey, black, beige, terracotta,

brown, white, clear.

installation/site workPosition within perp joint in

accordance with our

instructions and


NHBC/BRE. Observe

guidelines for increased

number in certain

applications/lengths of

installation. Ensure units are

clean and unrestricted.

bill of quantitywordingDual-purpose Euroweep-

vents from Cavity Trays of

Yeovil, Somerset

BA22 8HU (01935 474769).

Colour = .....

Introduce Euroweep-vent

units into perp joints to

facilitate discharge of water

from all discharge cavitrays

and all lintels (or specify

introduction within masonry

for venting purposes).





details.

related products andapplicationsFor alternative weepvents, see

Type W and small weepvent.

Euroweep-vent.


The Euroweep-vent offersan alternative to the Type Wweepvent. Its compact sizeoffers increased versatilityas it may be successfullyused where the masonrymodule height is restricted.The smaller aperture withinthe perp joint does notcompromise dischargebehaviour and water has thebenefit (as with the Type W)of a baffle protected exitroute. This product isextensively used in NorthernEurope and Beneluxcountries.BS.5628-3:2005 advises:“Proprietary devices may beinstalled to form weepholes.They may be designed todrain the cavity but preventthe ingress of wind-drivenrain”. The Euroweep-ventprovides all functions andcan also be used as a perpventilator.

technicalobservationsDual function.Integral baffles.Vertical front.Branded with name andlogo as proof of type andaccompanying warranty.

The upgraded Euroweep-ventfeatures a vertical front.

9mm

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Type X Cavitray for gable abutments

phone01935 474769 fax


cavitytrays.co.uk

• High performance approved cavitray for abutments

• Adjusts to cavity width - ensures correct relationship

• Integral anticapil features and integrity strip


• Clear cavity compartment area - unobstructed flow

• Attached shaped flashing secured in bosem jaw

49

High performanceType X cavitray offersunequalled benefits.

yy

problemHow to damp proof and flash

where sloping roofs abut

cavity walls. .

introductionEvery stepped and every

staggered gable abutment

must be so constructed to

prevent rainwater and

dampness from penetrating

below the abutting roofline.

This is because the external

skin changes status below

the roofline and becomes an

internal skin. Accordingly, any

preformed system must meet

three basic requirements:

1 It must prevent dampness

from penetrating below the

critical stepped roofline.

2 It must externally

weatherproof and flash the

physical roof/masonry

intersection.

3 The arrangement must

always protect the inside skin

also from becoming damp.

The high performance Type X

cavitray fulfils all such

functions, whilst speeding up

operations on site and

ensuring a good and known

quality of build.

solutionType X cavitrays combine the

functions of cavity DPC and

roof lead flashing.

Tray installation is very

straightforward and in a

typical brickwork application

the bricklayer lays one tray in

every course, following the

slope of the roof. All trays and

the projecting lead flashing

are flush-pointed as the

masonry is raised.

Thus the usual requirement

to rake out joints and return

to point-in flashings at a later

date is eliminated.

The bricklayer having built-in

the trays whilst raising the

wall has completed his work.

Trays are manufactured with

two choices of lead flashing

lengths. Short lead flashings

are suitable to dress over the

upstand of a secret gutter or

soaker.

Alternatively, long lead

flashings may be dressed

across the roof tile. Under

such circumstances, roof tiles

must be suitably ‘shaped’ ie:

not flat. At a later date when

the roof surface is complete,

the plumber has only to dress

the flashings.

cavitrays suit allcavity widthsType X gable abutment

cavitrays incorporate an

adjustable hinged back

upstand which is rigid and

self-supporting. Accordingly,

upstands do not require

building into the inside skins.

The cavity upstands

automatically adjust to suit

the cavity width in question.

This is a most important

consideration when one

appreciates that the as-built

cavity width is not always the

as-intended cavity width.

The standard Type X cavitray

will suit cavity widths from

50mm up to and including

140mm automatically.

This feature (or to 200mm

with extended upstand) also

eliminates the necessity to

raise both skins of the cavity

wall together.

course sizesThe standard Type X cavitray

is designed to suit standard

brickwork with approximately

75mm courses. Type X

cavitrays are also supplied to

suit other walling materials.


The airtightness of theinner skin (and thus therequirements of Part L)can be compromised withsite fabrications regularlyinterrupting inner skinbonding (following the roofpitch). The cavity upstandof the Type X cavitray doesnot enter or interfere withthe bonding so the skinremains unpunctuated.

The original code ofpractice 121:101:1951showed a cavity DPCarrangement with a 75mmupstand. We alwaysconsidered this far toosmall an upstand in ourexperience for new workapplications. Eventually thenew code of practicerevised the upstand heightto 150mm, a dimensionwhich is now prominent inBS5628. However, it isinteresting to note that notall manufacturers produceto this stipulated height.Type X cavitrays havealways been produced tothis dimension, prior to anyBS enforcement, followingour own evaluation. Testshave also established thatwater can be forced undersome damp-proof coursesif constantly high pressuredifferentials exist. Thus therequirement for all trays tobe bedded on mortar toachieve solidity of bondand to ensure wind-drivenrain cannot penetrateLong lead flashing for dressing directly

over roof tiles.

Short lead flashing for dressing overupstand of soakers (Shown in widerpart insulated cavity).

Trays are handed. As youview the gable, the left-handtrays discharge to the leftand the right-hand traysdischarge to the right.

Left-handintermediatetray

Right-handintermediate

tray

* Standard product accommodates cavityup to 140mm. Specify flap extension forcavities up to 200mm.

*

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tray typesRidge tray

This unit straddles the ridge.

It has open ends and thus

allows water to discharge to

the left or right.

Intermediate tray

Tray is supplied handed and

built-in each course up the

rake of the roof. Each tray

has an end upstand, thus

water can only discharge via

the open end into the tray

below.

Catchment tray

This is similar to an

intermediate tray, but it has

upstands to both ends. Its

function is to receive water

from the intermediate trays

above and to discharge this

collected water through a

weepvent. supplied with every

catchment tray.

Internal/External angles

An angle tray is used instead

of a catchment tray if the

abutment ends or returns

on a corner. An angle may

also provide a link with

horizontal trays.

tray variationsThere are variations of the

above tray types. We refer to

and recommend the use of

our free design and advisory

bureau to ensure the correct

trays are supplied. We will be

pleased to prepare our

recommendations schedule

and quotation from your

drawings. A proposal is then

submitted for your

consideration.

traditional build ortimber-frameThe adjustable cavity upstand

of the Type X cavitray means

the trays are suitable for both

traditional and timber-frame

construction.

cavity insulationType X cavitrays comply with

the requirements/


Specifiers Guide for Cavity

Insulated Walls. Type X cavitrays

permit the insulation selected

for use within the wall to be

maintained throughout the

structure.

refurbishmentprojectsType X cavitrays are suitable

for insertion into existing walls.

Please see separate page entry.

sizesType X cavitrays vary in size.

The more shallow the roof

pitch, the longer the tray. This

factor is automatically taken

into account. You need simply

state the roof pitch. Cavity

size accommodated = 50mm

to 140mm.

materialInjection moulded solid DPC

thermostable

petheleyne/polypropylene for

integrity of manufacture and

service. Lead flashing to

BSEN 12588:1999 cold rolled.

colourBlack and natural lead.

beneath same. The base ofevery Type X cavitray isunique as it incorporateswater bars which act asdrips to prevent dischargerun-back. However, inaddition, these water barsalso act as gauges whichpermit every cavitray totake up the exact andcorrect amount of mortardepth every time a tray isplaced in position. Use of the petheleynederivative of polypropyleneis the best performingmaterial following ourtesting procedures. Itpromotes the maximumservice life and should notbe confused with systemsmade of alternativematerials.

The unique bosem jawanchors the attached leadflashing to the tray, thussatisfying therecommendations thatflashing should be built-inas work proceeds ifpossible. During theoriginal Agreement Boardcertification/approval, it was remembered thatthe Type X cavitray was thefirst cavitray to be thesubject of a GLC approvalbulletin which advised useof the tray without furthermeasures when usedwithin London boroughs. On severely exposed sites,gable flashings may besecured if desired, usingconventional fixings.

High performance Type X Cavitrayused above canopy roofintersection

Standard brickwork courses.

75mm

Intermediate tray

Ridge tray

External angleunder an intermediate

Catchment trayunder anintermediate

Adjustable upstand accommodatesthe ‘as-built’ cavity width.

* Standard product accommodates cavityup to 140mm. Specify flap extension for

cavities up to 200mm.

*

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The Type X cavitray may be used in partially insulatedand fully insulated cavities. Specific advice is givenfor your proposed construction specification.

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how to calculate thenumber of traysrequiredOn a typical gable it is easy to

calculate the requirements.

Count the number of courses

and that will give you the

number of trays required for

each slope. Remember to

identify each slope as being

left-handed or right-handed.

At the bottom of each slope a

catchment tray is required.

All the trays running up the

slope are standard

intermediate trays. At the top

of the slope at ridge level it is

usual to incorporate a ridge

tray. In a staggered abutment

situation, the procedure is

identical except a ridge tray is

normally not required at the

top of the slope. At all times

remember to identify the

handing of the gable and

clearly mark where the left-

hand or right-hand cavitrays

are required.

installation/site workTrays are bedded on mortar at

each course level. The setting

up of a dummy rafter or chalk

line provides an easy location

method requiring the installer

to align only the inboard

corner of every tray to the line.

All positions and overlaps are

thus correctly established

automatically. The drawing

demonstrates a typical

installation. All trays and all

masonry is mortar bonded.

Full instructions accompany

every consignment. If in any

doubt, do not proceed but

telephone our Helpdesk for

immediate service.

bill of quantitywordingApproved Type X gable

abutment cavitrays from


Somerset BA22 8HU

(01935 474769).

Type X cavitrays to suit .....

(state pitch) pitch roof,

complete with attached code

4 lead flashings (or code 5 if

specified) to dress over ....

(state tiles or slate upstand of

secret gutter or soaker).

Standard brickwork coursing

(or state otherwise).

Cavity size = .....

Lay within mortar bed, one

per course, up the slope.

Specify total number of

handed intermediate, ridge,

catchment and external

angles..


details.

summaryType X cavitrays are unique,

and eliminate the need for

the usual lead cutting and

lead flashing on site.

Our products also eliminate

all wastage, eliminate all

cutting of the DPC, eliminate

fixing and gluing of the DPC

whilst also eliminating the

need to point-in after

installation. Cavity widths are

accommodated automatically.

The latest BS.5628-3:2005

qualifies on pages 62/63

that proprietary systems are

available for stepped and

staggered gable abutments.

The type X cavitray system is

the compliant proprietary

stepped tray system.

Our Technical Advice

Representatives can visit the

site following delivery, to

ensure a thorough

understanding and

appreciation of the most

advanced combined DPC

and flashing systems

available.

Our proposals and products

guarantee site quality and

site peace of mind - whilst

providing you with an all-in

known total cost.

The high performance

Type X cavitray offers further

benefits. See next page.

technicalobservationsAdjustable cavity upstandaccommodates the ‘as built’cavity status, rather thanthe anticipated status. Water drip bars eliminateunderbase track-back.Correct mortar beddingdepth. Integral cavitraysealing flap links with uppertray. This feature on the trayend upstand arrestshorizontal tracking at thisvulnerable point. Integralflashing projects fromwithin the front edge of tray,not under or against thetray base. This bosem jawarrangement ensures unionintegrity. Corner watercheckprevents discharge at this point - an importantconsideration on exposedsites. The corner gussetalso ensures correctlocation within brickwork asit stops trays beingpositioned too far forwardor too far back. Uniqueoverlapping flashingarrangement arrests anywind-driven rain whichwould be in contact withthe building fabric withconventionally steppedrunning flashings.High performanceclassification.Branded with name andlogo as proof of type andaccompanying warranty.Conformity certification/liability document.

Stepped abutment

Staggered abutment


*

Type X Remedial for gable abutments - remedial(existing) applications†

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• Fitted from outside, with minimum of masonry removed

• Cavity upstand adjusts to suit the ‘as found’ cavity width

• Base bars ensure correct mortar bedding depth


• Attached flashing ready-shaped for dressing

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remedial (existing)applicationsThe benefits of using the

preformed Type X cavitray are

described on the previous

pages. Type X is also suitable

for existing work applications,

as well as for new work. The

construction of a new pitched

roof abutting an existing

cavity wall normally

necessitates the introduction

of an accompanying cavitray

system. This is because the

original outside skin becomes

an internal skin below the

new roofline. Building

Regulations stipulate

measures must be taken to

arrest any dampness.

The upstand of the Type X

cavitray is hinged, which

permits it to be turned to the

horizontal status. In this

position, the standard Type X

cavitray takes up the height of

one brick course only, which

allows its introduction into a

cavity wall with the minimum

of disturbance to the

surrounding structure.

The cavitray is bedded onto the

mortar as it is pushed into

position, and at the same

time the cavity upstand is

allowed to take up its correct

angle within the cavity. The

amount of masonry which

must be removed is kept to

an absolute minimum

compared with most methods.

The task of introducing the

DPC tray at each course up

the roof slope does involve

careful application and

attention. Cutting out,

especially on a steep slope,

involves masonry removal

vertically staggered and

observance of the usual

precautions plus the

introduction of slate pinning

should be considered.

Compliance with the Building

Regulations necessitates the

introduction of the stepping

DPC system, and the Type X

enables a difficult ‘existing

gable’ task to be undertaken

in perhaps the easiest

possible manner.

High performance Type X cavitrayscan be inserted into an existing wall.Typical applications includeintroduction when a building is addedto an existing structure or where theoriginal DPC has failed.


Type X cavitray hinged trayback has the addedadvantage of taking up theas-found cavity width ratherthan the as-anticipated.Being self-supporting, theType X upstand does notrequire any mechanicalfixing to the face of theinside skin. Use of the TypeX cavitray meansdisturbance of the existingmasonry is kept to anabsolute minimum. Type Xcavitrays have attached leadflashings secured within aunique protective bosemjaw. Use of the petheleynederivative of polypropyleneis the best performingmaterial following ourtesting procedures. Itpromotes the maximumservice life and should notbe confused with systemsmade of alternativematerials. Such benefits arenot offered by any otherproprietary system.

†This section should beread in conjunction withType X pages.


Clear cavity compartment area is unobstructed bytroughs, ribs or stiffeners. This is possible becauseof our quality of material and quality of materialthickness. Such a clear cavity compartment area isessential to prevent mortar bridging and to complywith the NHBC/COP requirements.

Adjustable cavity upstand accommodates the ‘as-built’ cavity status rather than theanticipated status.

Corner water-check prevents discharge at this point, an important considerationon exposed sites. Installation is also fasterand easier, and the corner gusset ensurescorrect location within the brickwork as itstops trays being positioned too farforward or too far back.

Water drip bars eliminate under-base tracking. Correct mortar bedding depth is also established as bardimensions harmonize with front of tray section to aidstability and mortar integrity.

Upstand turned to horizontal status.

Additional benefits

Unique overlapping flashing arrangementarrests any wind-driven rain.

Conservatories and the NHBCNHBC Standards Extra qualifies:‘Where the conservatory abuts the existing external walls of the house, a steppedcavity tray should be provided above the roof abutment. The tray will need to belinked to a stepped flashing’. Compliance can be achieved using the Type X Cavitray.

Integral cavitray sealing flap links with upper tray. This feature on the tray endupstands arrests horizontal tracking atthis vulnerable spot.

* Standard product accommodates cavityup to 140mm. Specify flap extension for

cavities up to 200mm.

*

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Type X Multicourse for gable abutments -

multicourse applications†

phone01935 474769 fax


cavitytrays.co.uk

• Ready-shaped attached lead flashing



• Sizes to suit: All course heights

All masonry thicknesses

All cavity widths

All pitches of abutment

53

Multicourse cavitrays are available in dimensions

to suit all masonry course heights and all thicknesses of external skin.

The Multicourse tray style varies pending course height and masonry thickness.

The illustration is an example of one such style.

yy

multicourseapplicationsBrickwork courses accept

standard Type X cavitrays.

However, different course

sizes are sometimes

encountered and a range of

gable abutment multicourse

cavitrays are available to

accommodate different

coursing heights. Multicourse

cavitrays are based on the

design of the Type X. They are

proportioned to accept a

variety of walling materials

and dimensions. Examples

include reconstructed, faced,

natural and concrete

masonry, in course heights of

100mm, 125mm, 150mm,

175mm, 200mm, 225mm.

The cavitray upstands are

hinged to suit cavity widths

from 50mm up to and

including 200mm. The tray

base dimension is extended

to suit whatever thickness of

masonry is used to construct

the external skin.

As an example, a nominal

150mm backing block would

have a base depth

requirement of 250mm +

cavity allowance. All depths

can be accommodated. The

height of the end upstand on

each multicourse tray is of a

size to match the masonry

course height. As each tray is

bedded and positioned, the

underside abuts the end

upstand of the lower tray.

Thus the stepping DPC line

is continuous, adopting the

form of a staircase with

connecting treads and

connecting risers. The

continuity is essential if

dampness is to be arrested

and prevented from

penetrating or tracking below

the stepping DPC line.

The multicourse cavitray

accommodates the DPC

requirements within the

masonry, whilst the integral

lead flashing projects and

weatherproofs the roof/wall

junction externally. The lead

flashing is available in long

or short format, to suit the

construction detail. To calculate

and order your requirements

of multicourse cavitrays, follow

the instructions outlined on

the Type X pages, but

substitute the course size you

are using instead of the

75mm course size.

Remember to check also the

depth (thickness) of the

masonry you are using, to

ensure the base size of the

tray is appropriate. Our design

and advisory service is

available without charge.

Schedules and quotations

submitted for approval.

design considerationsThe Building Research

Establishment (digest 380)

refers to the use of flexible

DPCs to create a cavity tray

and correctly identifies the

difficulty in achieving fully

sealed joints, especially when

crossing the cavity. Flexible

materials require support and

dictate that an accommodating

course is found on the inside

skin. The inside skin is usually

constructed of a different

material so the course levels

are commonly at an

inconvenient or unsatisfactory

height. This dilemma is also

apparent with timber-frame

construction which relies upon

mechanical fixing through the

vapour barrier. Multicourse

Cavitrays have an upstand

which is rigid, freestanding

and eliminates the need for

support. It adjusts to match

the cavity width to ensure

compatibility.

related products andapplicationsSee Type X cavitray for gable

abutments.


During the 1960s and1980s, a considerablenumber of evaluation testswere conducted with damp-proof course tray shapes.

Small deviations in levelsbetween outer and innerskins often exist, andpreformed systems whichrequire building-in can fail toline up on site when it isdiscovered that courseshave ‘drifted apart’. Whilstwe have witnessedsuggestions to mechanicallyfix to the inside skin orperhaps incorporate someform of inside-skin-downward-flap, we haverejected such methods. Ourtests highlighted that suchobservances were notalways easy to achieve onsite. (To mechanically fix toan inside skin which isusually green is difficult,whilst separate flapsemerging from a blockworkinside skin can only emergeevery 225mm, and withbrickwork courses in theouter skin at 75mmcourses, one is faced with acompromise or a gap.)Certainly any form ofadditional work to the insideskin is to slow up buildingoperations and considerablyincrease costs.

†This section should beread in conjunction withType X pages.

Multicourse Mix This example showsa combination of trays to suit 75mm100mm and 150mm coursings.

Multicourse Regular Wide Front to BackDimensions. The natural hamstone isbuilt against a concrete backing blockresulting in an external leaf of 250mmthickness beyond which is the cavity.Thus the trays have extended front toback dimensions.

Multicourse Regular 225mm coursestrays are used throughout this example.


*

Perform Synthetic Flashing

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• Thermally stable

• Malleable / stretchable

• Choice of flashing colours

• Available attached to some tray types or in rolls

• No scrap value

54

problemSelecting an alternative style

of flashing for use in low level

applications and/or areas

where theft of conventional

metal flashings is a

consideration.

introductionMetal flashings are

appropriate for use in most

locations, but alternatives are

requested where there is a

risk of theft or where there is

a compatibility issue with

different types of metals

converging. An alternative to

metal flashings is also

commonly sought where

water reclamation / recycling

systems are deployed and

metal oxidisation is of concern.

solutionPerform is a synthetic

flashing with no intrinsic

theft value and offers

compatibility with most

building materials. It is a

composite material

consisting of an aluminium

mesh enveloped within silian-

modified polymer rubber.

Perform flashing, is non-

permeable, and offers similar

malleability to lead flashing.

It will hold to shape once

dressed (it is thicker than

code 4 lead flashing) but can

additionally be secured in

place with adhesive if

required. It offers the

specifier an alternative to

metal flashing with a choice

of colours.

Perform is lapped and dressed

in the same manner as lead

flashing. It is resistant to

temperatures between –20

and + 70 degrees, UV and

Ozone resistant and weighs

3.6kgs/m².

sizesPerform is available as an

alternative flashing with Type

X and Type G cavitrays.

It may also be purchased in

the following roll widths:

150 x 4m

250 x 4m

300 x 4m

450 x 4m

1250 x 4m

materialSilian-modified polymer

rubber with aluminium mesh

within.

coloursLight grey, terracotta, black.

bill of quantitywording(Use standard tray

specification as applicable and

stipulate Perform flashing is

required)

Type …. Cavitray by Cavity Trays

of Yeovil Somerset BA22

8HU (01935 474769) ……..with

Perform flashings attached,

colour……

For rolls state quantity, width

and colour.


Perform flashing hasrecently been assessed andgranted BBA certificate09/4681. The material hasbeen used extensively inEurope and Australia since2002 and has undergoneaccelerated testing andanalysis by the DanishBuilding and UrbanResearch Department. Ithas been identified as anon-toxic and friendly to theenvironment alternative totraditional flashing. Assynthetic flashings are notmanufactured by CavityTrays and are excluded fromour warranty.When trays are suppliedwith Perform flashingsattached the tray is subjectto the performancewarranty issued by CavityTrays Ltd and the Performflashing is subject to thePerform manufacturerswarranty. Goods are offeredon this basis only.

yy *

* Standard product accommodates cavity up to 140mm. Specify flap extension for cavities up to 200mm.

Type X Cavitray with black Perform flashing.

Type X Cavitray with terracotta Perform flashing.

Type X Cavitray with grey Perform flashing.

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Advantage Rangeunleaded gable abutment trays

phone01935 474769 fax


cavitytrays.co.uk

problemDPC cavitray for stepped and

staggered gable abutments.

introductionPreformed cavitray without an

integral lead flashing attached.

May be used as an alternative

method of creating the damp

course element only where a

sloping roof abuts a masonry

wall. This product is named

Advantage, as it offers benefits

not available from any other

unleaded cavitray

manufacturer.

solutionThe Advantage unleaded

gable abutment cavitray

differs from the Type X

cavitray, described on previous

pages. The Advantage

unleaded gable abutment

cavitray is intended for use by

installers who wish to introduce

their own flashing medium at

a later date. Each unit is

moulded in solid DPC

material and has a variable

cavity upstand facility. When

incorporated within an

external skin, the mortar is

raked out underneath the base

of the tray whilst it is still

green. At a later date a lead

or other suitable flashing is

cut and introduced within the

raked-out joint. Flashings

should be firmly secured by

wedges as necessary,

following which dressing of

the flashings may take place.

There is a requirement for the

bricklayer to return to site to

point-in flashings.

course sizeThe Advantage unleaded

gable abutment cavitray is

designed to suit standard

brickwork courses of

approximately 75mm height.

the range of traysAdvantage unleaded

catchment tray. These are

built-in at the bottom of the

slope and their function is to

catch water and direct it to

the building exterior via

weepvents.

Advantage unleaded

intermediate tray. These trays

are handed and are built-in

each course up the rake.

Advantage unleaded ridge

tray. This unit straddles the

ridge.

Advantage unleaded external

angles. These are used in

place of unleaded catchment

trays when commencing

laying from the corner of a

building.

sizesStandard tray of 330mm length

may be used for roof pitches of

17.5 degrees upwards. Specify

left or right hand. Suits cavities

from 50mm up to 140mm.

materialSolid DPC, injection moulded.

Optional polystyrene rake-out

strip.

colourBlack.

installation/site workFull installation instructions


Build-in observing relevant

NHBC and British Standard

requirements. Please refer to

Type X pages which describe

the manner in which trays

should be calculated, handled

and installed. Bed each tray

on mortar, do not dry bed.

To achieve correct tray

position in relation to roofline,

the inboard corner of every

tray in every course should be

75mm off the finished roof

surface. Rake out under tray

whilst mortar is still green to

a depth of 25mm minimum,

to create a recess into which

a lead flashing may be

introduced at a later date.

Use tray types as stipulated

within the instructions which

accompany every consignment.

Do not dry bed any masonry

or any tray. If in doubt do not

proceed, but seek advice by

telephoning our Helpdesk.

bill of quantitywordingAdvantage unleaded gable

abutment cavitray from Cavity

Trays of Yeovil, Somerset.

BA22 8HU. (01935 474769).

Advantage unleaded trays to

suit...... roof pitch. Standard

brickwork coursing. Cavity

width...... Bed within brickwork,

one per course up the slope,

ensuring each tray is within

struck mortar joint and flush-

pointed as work proceeds.

Rake out underneath each

tray to LSA guidelines, prior

to mortar curing. Observe

manufacturer’s installation


trays. Specify total number of

all tray types required.


details.

related products andapplicationsSee Type X for gable abutment

cavitray with attached lead

flashing which reduces labour

costs whilst offering increased

benefits.

• Standard trays suits pitches from 17.5°

• Cavity width adjustment 50mm to 140mm

• Solid moulded DPC tray with integral stopends


Advantage trays are also availablewith a rake-out polystyrene stripon the underside of the tray front.Rake-out strips attract a premiumand are supplied only if specificallyrequested on the order.


Originally conceivedfollowing requests for asystem which might beincorporated into masonrywalls, against which apitched roof extension mightbe added at some laterdate. A variety of flashingmaterials may be introducedunder the tray and thisexercise/ responsibility isleft as an on-siteundertaking.The name ”Advantage“ wasgiven to this unleadedsystem following anappraisal of all unleadedsystems offered in the U.K.The clear cavitycompartment area coupledwith the adjustable cavityupstand whichaccommodates numerouscavity widths, makes thissystem extremely user-friendly. It does not suffer theinability encountered withfixed upstand trays toaccommodate cavity widthvariations and deviations.The B.R.E. investigation intotraditional housing faultsidentified over 75% of allexamined faults werejudged to be as a result oflack of care rather than lackof skill. If an unleadedabutment cavitray system isrequired, the Advantagerange promotes an enviableability to match with thecavity width/detail actuallyconstructed.

55

Curved Cavitray -on planconcave and convex

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problemHow to create damp courses

for use within curved

masonry, cylindrical towers

and round structures.

introductionWhen a cavity wall is curved

on plan, special consideration

must be given to relationship

between the masonry skins

and the manner in which all

damp courses and flashings

function. The base of every

cavitray must be shaped to

match the masonry arc,

whilst the cavity upstand is

usually sectioned, to permit

maximum flexibility and cavity

protection. When curved

cavitrays are supplied with an

attached lead flashing to dress

to an abutting roof, there is

the additional consideration

of pitch differential. A

constant roof angle abutting

a curved wall has numerous

intersection angles at various

points around the

intersection arc. Concave

and convex curved walls

always require special

attention.

solutionThere are four main types of

concave or convex cavitrays,

commonly employed within a

curved cavity wall.

common openings - curved

Window and door openings

within a curved cavity wall are

generally detailed with a

matching curved lintel. In

such instances, an arched

version of our Type C

common opening cavitray

with a sectioned cavity

upstand is usually

appropriate.

Each curved cavitray

harmonizes with the lintel

shape, and is extended

beyond the lintel length to

ensure arrested water is

discharged clear of the

support medium, via weeps.

In instances where the

masonry curve is very slight,

a decision to use straight

lintels to cross and support

through the projected curve

path is sometimes possible.

The cavitray is likewise

straight but widens at either

end where the lintel line is

indented, to provide full DPC

spread and cover.

arresting barriers - curved

These are similar to the

above, but the dimension of

the base within the exterior

leaf is smaller, as an arresting

barrier does not project

through the full width of

masonry. Its purpose is to

arrest and minimise any

wash of water prior to an

exposed or otherwise

vulnerable feature or detail.

horizontal intersections -

curved

Modified versions of the Type

G general purpose cavitray

are available for use at

horizontal intersections with

a curved wall. Typical

applications include the

abutment of a bay window or

flat roof. Depending on the

arc dimensions, an optional

lead flashing can be supplied

already attached.

sloping abutments - curved

The intersection of a pitched

roof against curved masonry

necessitates a three-

dimensional approach.

The dimension of every

cavitray is individually

structured, to take into

account the arc of the wall and

the masonry coursing, whilst

optimising cavitray length

against roof pitch variance.

A simple example is a

pitched roof (P) partially or

fully enclosing a convex wall

of a masonry tower (similar

to a lighthouse). The tray

length (L) is established per

masonry course (MC), whilst

allowing for intersection pitch

variance (IPV) around the

tower diameter (D).

The optimum flashing length

is established to provide the

requisite overlap protection.

The length of every tray and

the flashing shape is

reviewed at every course,

because the intersection

pitch changes. In the case of

a fully enveloped circular

tower, this variance actually

creates two horizontal

• Damp-proof trays and flashing in one unit

• Ready to use module cavitrays on bespoke basis

• Cavity width adjustment ensures compatibility

• Integral stopend and water-check

• Permits easy regulation compliance


Give consideration toincorporating arrestingbarriers also, within anyconvex wall or concavestructure where the amountof masonry (absorptionarea) above intersectionexceeds 12 sq. metres.When the abutting roof isfinished with plain tiles, thepitch is actually reduced asplain tiles slope less steeplythan the rafters upon whichthey are laid. Checksuitability when used at alow pitch. Secret gutters or similarweatherproof channels/barriers are required whereroof-slopes run into tapered,restricted or curvedelevations. The cavity upstand oncurved trays generally risesvertically and incorporates asectioned hinged overlaptop portion. The leadflashing is normally integral,but is occasionally suppliedseparately from the curvedcavitray if the constructiondetail application dictates. Any masonry expansionjoints should be identified topermit an appropriatemovement link-tray to beincorporated across suchjoints. Curved trays are alsoavailable for use withindiaphragm walls. Flushpointing is recommendedon circular tower/curvedstructures and designersshould consider carefullythe masonry medium andtype of mortar.

Convex commonopening tray

Convex arrestingbarrier

Convex horizontalintersection tray

Curved lintel and curved masonryprotected by cavitray of equal radius.

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Curved Cavitray -on plan

concave and convex

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intersection points (at the top

and bottom of the circle) -

regardless of the pitch of the

abutting roof. We also

calculate the maximum cavity

compartment area that can

be linked/over-sailed within

the cavity, as curved

structures tend to inhibit the

conventional flow path of

penetrating rainwater.

Please submit dimensioned

elevations and plans showing

the curved masonry and any

abutting roofs. We will be

pleased to advise product

prices and quantities

necessary to damp-proof and

flash (if applicable) the

curved abutment.

Purpose-made in all sizes to

suit individual projects.

materialBS Polypropylene and

Petheleyne, with BSEN

12588: 1999 lead flashing.

colourBlack cavitray units with

natural lead flashing attached

if applicable.

installation/site workSpecific instructions for

installation accompany all

goods.

Site instruction is also

available to ensure building-in

is in accordance with the

relevant British Standards

and codes of practice.

bill of quantitywordingPurpose-made curved

cavitrays by Cavity Trays of

Yeovil, Somerset. BA22 8HU.

(01935 474769).

Incorporate when raising

external skin of cavity wall in

accordance with

accompanying instructions

and good building practice.

Request conformity/liability



details.

related products andapplicationsFor non-curved versions of

cavitray, see individual pages

of named products.

• Damp-proof trays and flashing in one unit

• Ready to use module cavitrays on bespoke basis

• Cavity width adjustment ensures compatibility

• Integral stopend and water-check

• Permits easy regulation compliance

technicalobservationsTo three-dimensionally cut,form and build in appropriatedpc integrity up a slope is adifficult site undertaking,especially on curved work. The airtightness of the innerskin (and thus therequirements of Part L) canbe compromised, if the innerskin bonding is regularlyinterrupted. The cavity upstand of theType X cavitray does notenter or interfere with thebonding. Thus the inner skinremains airtight.

Branded with name andlogo as proof of type andaccompanying warranty.

Despite the angle of theabutting roof being constant,

the angle of intersectiondiffers on every course,

depending at which point itmeets the curved wall.

Convex slopingabutment tray

Typical example of gable abutmentagainst convex masonry (see linedrawing below).

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Type Ystone mullion assembly cavitray

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problemHow to protect mullion

window surrounds against

damp penetration.

introductionCast stone is defined as ‘any

material manufactured from

aggregate and cementitious

binder, and intended to

resemble in appearance, and

be used in a similar way to,

natural stone.’ Whilst the

appearance is that of natural

stone, the behaviour in terms

of water penetration varies,

and manufacturers of pre-cast

mullions and architectural

features stipulate the use of

strategically placed damp

courses, to achieve good

serviceable life from the

components. Cavity Trays Ltd

has developed a range of

preformed cavitrays

specifically for mullion

assemblies.

solutionMullion window assemblies

manufactured from synthetic

stone require a total of three

cavitrays to maintain damp

course integrity across the

window head. At the highest

level bedded on the

decorative label-mould

(string-course) is the first

cavitray, the purpose of which

is to act as an arresting

barrier. It receives the wash

of cavity water from the

masonry above and

discharges it via weepvents

positioned at the extended

tray ends - well clear of the

side mullions.

The second cavitray is shaped

to rest and bed into the

supporting metal angle, which

provides the load-bearing

qualities to the assembly. There

is very little cavity water at this

level, the majority having been

stopped at the higher level. The

third cavitray provides a vertical

barrier between the lintel on

the inside skin and the

synthetic stone head. All trays

are self-supporting and do not

require building-in to both

skins. Type Y mullion assembly

cavitrays ensure the standard

of DPC protection is

regularised to all openings.

sizesAvailable for all mullion

assemblies. State make, model,

and confirm cavity width.

material Polypropylene.

colourBlack.

installation/siteworkIncorporate and bed Type Y

mullion assembly cavitrays

into position at appropriate

stage in construction,

observing full instructions

that accompany every

consignment. Build-in perp

weeps in positions indicated.

bill of quantitywordingType Y mullion assembly

cavitrays to mullion openings,

by Cavity Trays of Yeovil,

Somerset. BA22 8HU

(01935 474769) Incorporate

whilst assembling and raising

masonry, observing

accompanying instructions.

Mullion reference......

Number......


details.

related products andapplicationsSee Type C for standard

openings and lintels.

See Type D, H, V and

Quickcloser for vertical reveal

closing and damp-proofing.

• Preformed for immediate use

• Packaged per opening

• Consistent detail with regulation compliance

• Different cavity widths accommodated


The original BS6073:Pt1,1981 made no reference tothe maximum waterabsorption requirements ofthe synthetic stone,whereas BS1217:1986specified the limitations.This resulted inreconstructed or syntheticstone varying in terms ofwater absorption andporosity, and the behaviourbetween units of seeminglysimilar design differed to agreat extent. It isrecommended carefulconsideration is given at alltimes to the damp-proofingaspects of installations, andthe three cavitray approachis adopted, so water isremoved from the cavitybefore reaching the level ofthe mullion assemblies.Up to 2.25 litres of waterper hour can penetrate onesquare metre of masonry. Ifthe absorption area (theextent of rising masonry)above a mullion feature isextensive, the (pro-rata)flow and demands for watercontrol and evacuation areobvious.


Cavity Trays Limited have developedtrays to suit the stone mullion detail.The trays are self-supporting and donot require building-in to both skins.

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Type Z Cavistrap strap to fix and support flexible DPC

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problemHow to adequately secure

polymer, bitumen and

polythene roll DPC.

introductionPolymer, bitumen and

polythene roll DPC is still

extensively used on

construction projects and such

conventional materials require

the operative to undertake a

degree of on-site fabrication

work. Cavistraps are preformed

and rigid moulded lengths

designed to evenly retain and

support DPC within the cavity,

against the inside skin. This

particular requirement

commonly occurs when a DPC

upstand is to be secured to a

face of a cast concrete surface

or similar finish in which there

is no supporting chase or

retaining feature available.

A similar situation can also

occur when blockwork or

composite inside skins, rise

off ringbeams. Type Z

cavistraps are supplied in 2

metre lengths and are pre-

drilled to accept fixings of

most styles. The shape of the

cavistrap is slightly arched,

with the outside edges

feathered. The arc promotes

an even distribution of

pressure against the DPC,

as the fixings are tightened,

whilst the feathered edges

help take up irregularities

originating from the face of

concrete or similar.

Cavistraps provide an easy

way of positively securing

DPCs against a solid surface.

The standard width cavistrap

of 30mm is recommended

for most applications.

sizesCavistrap =

2000mm long x 30mm wide.

Predrilled with 4mm holes at

150mm centres.

materialPVCU.

colourBlack.

installation/site workMechanically fix Cavistrap in

position, utilizing the predrilled

holes at 150mm centres.

Ensure Cavistraps are

positioned to adequately

secure the rising DPC, and

fixings are tightened so the

straps apply an even pressure

throughout. Observe good

building practice and the

instructions of the DPC

manufacturer.

bill of quantitywordingCavistraps (state width) from


Somerset BA22 8HU.

Mechanically fix to secure

flexible DPC against inside

skin. Total run = ....metres.




details.

related products andapplicationsSee Caviroll for conventional

polythene DPC.

• Easy to handle and use

• Pre-drilled

• Shape accommodates surface irregularities

• Cost effective method to mechanically secure flexible DPCs


The profile is easy to use,and is moreaccommodating if theunderlying surface isuneven. If a bondingadhesive used against theinside skin face, cavistrapsare still recommended inaddition - as detailed inmany manufacturers’ fixinginstructions to whichattention is drawn.


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Masonry SupportCavitray Systems

problemThe efficient fabrication,

incorporation and functionality

of a dpc system within an

exterior skin built off a metal

masonry support system.

introductionWhen constructing off a

masonry support system, the

dpc is commonly incorporated

at a higher level than is ideal.

This is because of the

difficulties of bringing together

and achieving a consistently

profiled relationship between

the metal angle support and

roll-out dpc material. The

resultant practice of

incorporating the dpc a course

or two higher provides

protection – but not to the

maximum extent. Penetrating

water can be retained within

the masonry sitting on the

support angle. Furthermore,

pending the proximity and

cleanliness of the steel

assemblies, in some

circumstances water can track

inwardly towards the inside

skin. Use of a Masonry Support

Cavitray can eliminate such

shortfalls and speed up the

construction process.

solutionMasonry Support Cavitrays are

semi-rigid dpc’s supplied

preformed in ready-to use

lengths. They are specifically

manufactured to integrate with

whatever masonry support

system you are using.

Conventional roll material can

distort, sag and become

misplaced, but Masonry

Support Cavitrays being

preformed, overcome these

deficiencies. Their consistently

profiled shape also permits

incorporation at the optimum

course level, rather than at a

compromised level.

Cavitrays are self-supporting

within the cavity. However,

pending the profile selected

there is an option of

mechanically fixing the upstand

to the inside skin if required.

(See Cavistrap entry). Adjoining

lengths and angles formed by

mitre cutting are readily united

with the application of a cavitray

tape. Stopends and special

fabrications are available to

complement the system.

Wastage, misplacement, and

site errors can be eliminated

with use of the Masonry

Support Cavitray. Water

penetrating the external skin is

arrested by the cavitray at the

optimum level (see Designers

Comments) and evacuated out

of the structure via caviweeps

positioned within perp joints.

sizesPlease advise type of support

system you are using so the

appropriate profile can be

offered. Cavity widths

accommodated up to 150mm

maximum. Preformed lengths

of 1200mm and 2400mm.

Schedules can be prepared

detailing your site requirements.

Cavitray joint tape supplied in

rolls 100mm x 30 metres.

materialCavity biased Petheleyne /

polypropylene.

colourBlack.

installation/site workMasonry Support Cavitrays

should be incorporated at the




of BS5628 and Robust Details.

Ensure each length is correctly

position (Secure against inside

skin if required using Cavistrap).

Lengths and angles to be

joined using Cavitray tape.

Instructions accompany all

consignments.

bill of quantitywordingBespoke Masonry Support

Cavitray by Cavity Trays of Yeovil,

Somerset. BS22 8HU. (01935

474769). Build in to all masonry

support levels. Schedule

provided by Cavity Trays Ltd.

Measured metres run =

ordering/buildingregulationsSee inside back cover.

related products andapplicationsFor water evacuation see

caviweeps Type W, Beak, Euro

and Small Adjustable.

For optional mechanical fixing

see Cavistrap.

• Profiles to suit all types of support systems

• Maximum dpc protection against water ingress

• Available to suit all cavity dimensions

• Pre-shaped ensures consistent build quality

• Wastage can be eliminated


Parallel running with the angleof the support bracket ispossible to maximise thecavity compartment areawithout suffering distortion.This is not usually possiblewith conventional materialespecially where the bracketstyle protrudes or changesplane at the bracket top. Theuse of dual functioncaviweeps provides a waterexit route whilst also allowingthe cavity to breathe. This isimportant when one considersthe unventilated void that iscreated between steel supportand the underside of aconventional dpc installed onecourse higher. Cavity masonrywith consistent and balancedcavity ventilation andaccompanying waterevacuation is one of theobjectives. Such constructiondoes not suffer saturation andthe discolouration of masonrywitnessed in bands aroundstructures wherever anunventilated water-retentivevoid is present. Visualimpairment is thus minimisedin the long term.

technicalobservationsThis Masonry SupportCavitray utilises more thanone previously patenteddesign held within ourportfolio and additionally is arevised style.

Masonry Support Cavitray used withpistol brick. Cavitray has bias to take-up maximum cavity width. Optionalmechanical fixing against inner leafshown dotted.

Pistol brick tray.

Standardbrick tray.

Typical application. ExpansionJoint Stopends are alsoavailable to make provisionfor expansion and contractionand at the same time providecontinuity of dpc protection.

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SECTION TWOcloser products

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Type DIP Type D Interfacing Profile• Vertical dpc for all cavity widths• Rigid profile ensures consistency of build• Thermal break• Interfaces with cavity insulation• Eliminates thermal spiking

Type FWC Five Width Cavicloser• Acts as a dpc• Insulates the reveal• One model provides five size options• Straight reveal applications• Cavity widths 50mm, 65mm, 75mm, 85mm, 100mm.

Type H Cavicloser• Acts as a DPC• Insulates and introduces a thermal zone• Permits choice of frame position• Frame fixing when work proceeds or at later date• Closes cavity and accommodates a range of cavity widths• Cavity widths 50mm & 75mm (H1) or 70mm & 100mm (H2)

• Closes the reveal• Acts as a DPC• Integral Fins• New and existing structure applications• Insulates cavities from 40mm to 100mm wide

Sash Frame Insulated DPC• Acts as a DPC• Thermally insulates• Assured preformed detail• Permits upgrading of opening• All cavity widths accommodated

Type RC Refurbishment Closer• For insertion into existing cavities• Squeeze to fit insulation• Suits cavity range 40mm –100mm• Thermally upgrade when replacing windows

Type V Contract Closer

• For cavities 100mm to 170mm• Insulates the reveal• Closes cavity + acts as vertical dpc• Anti-capillary fins

Type D Damp Proof Course• Vertical damp-proof course• Vertical insulator suits all cavity widths• Robust and self-supporting - cannot sag• Eliminates danger of mortar bridging• Conventional build or attach to frame

• Closes cavity and acts as a DPC• Insulates the reveal• Cavity widths 50mm to 100mm• Eliminates need to cut and return masonry• Cost-effective standardised detail• Anti capillary fins

Quickcloser Closer with flexible insulation

Closing Cavity Walls is the title of our manual that details efficient ways to address Building Regulations + thermal, fire and acousticrequirements. Some closers address the same construction detail, but with a different emphasis. See separate publication.

Type V 170 Wider cavity contract closer

• Closes cavities up to 200mm wide• Function as vertical DPC• Insulates reveal• Permits choice of frame positions• Micro fins

Type WCA Wider cavity installations

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Cavi60 Type WCA Cavicloser• Acts as a DPC• For cavity widths up to 150mm• 60 minutes fire integrity rated stops• Micro fins • Accompanying stainless steel anchoring ties

Cavi90 Type H Cavicloser• 90 minutes fire integrity rating• Closes and insulates reveals• Acts as a DPC• Integral fins• Suitable in cavities of 50mm and 75mm wide

Cavi60 Type V170 Cavicloser• One hour fire rating• Cavity range 100mm to 170mm• Acts as a dpc• Closes and insulates reveal• Acoustic reduction insulator

Cavi240 Type PWIB• Fire-rated integrity barrier• Acts as a DPC• Reduces acoustic flanking

transmission• Available to suit all cavity widths• Preformed ready to use, will not sag or distort

Cavi60 Type SAF Stop• Acoustic barrier• Fire barrier• Protective shape prevents water tracking• Easy linking and lapping• For cavities of 100mm

Cavi240 Type CFIS• 240 minutes fire integrity rated stops• Easy friction fit• Accompanying moisture

protection measures• For cavity widths up to 100mm

Cavi60 MWR 200• One hour fire rated barrier• Acoustic barrier• Friction fit• 100mm to 200mm cavity range

Type GBFICS Ground Bearing Floor Insulating Cavitray System (for closing base of cavity wall)• Multi-functional one placement product• Radon and methane cavity barrier• Enhanced perimeter insulation• All cavity widths accommodated

Type GBPWIS Ground Bearing Party Wall Insulating System (for closing base of party cavity wall)

• Eliminates need for temporary formwork• Creates and closes cavity arrangement.• Establishes party wall spillage channel• Enhanced perimeter insulation• Multi-functional one placement product• All cavity widths accommodated

Cavi120 Type V Cavicloser• 120 minutes fire integrity rating• Acts as a DPC• Closes and insulates reveals• Anti capillary fins• Suitable in cavities from 50mm to 100mm wide

BespokeTraditional Closing Service

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Page 64

Page 65

Procedures: Construction on contaminated land

Type N Damp-proofing membrane with methane and radon resistantqualities.

Preformed barriers for installation in new-build properties atground floor level.

Sitesealer membrane for gas and damp-proofing

Page 67Methane Barrier for use withincavity walls

Preformed Petheleyne barriers designed to minimise theentry of radon gas into the building.

Page 68Radon Barrier for use withincavity walls

Discharge routes for trapped gases and trapped rainwater. Page 69Inlets and outlets

Outlets for gas andwater discharge

Reception sump To service evacuation of gas from below integrity shield. Page 70Gas Sump

Product type codes within each section are listed in alphabetical order. In some instances, products are then grouped by function.

Example: Under W the Type W caviweep is then followed by other types of weep.

SECTION THREEmembranes and barriers

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Procedures

When constructing on

contaminated land, the design

objective is to form an airtight

and therefore gas-proof

barrier across the whole of the

building including floors and

walls. Suspended concrete

floors, in situ or ground-

supported floors can be

accommodated, and the

appropriate barriers and

membranes supplied to

provide a fully compatible

integrity shield. Different types

of gas emission require

different types of protection

and the emission type must

be clearly identified.

Construction on contaminated

land must protect against the

entry into the building

envelope of dangerous gases

such as methane, radon etc.

Such measures are:

Type N sitesealer membrane

protects the oversite, creating

a combined DPC and gas

integrity shield.

Gas from contaminated land

can still enter the building

envelope if a protective

oversite membrane only is

used. It is necessary to

extend the integrity shield

through the cavity walls. This

is achieved using Petheleyne

cavity barriers.

Barriers are supplied in long

lengths, with accompanying

corners, angles etc.

A Petheleyne compatible

sealing strip permits

adjoining sections to be

positively lapped and united.

Similarly, the oversite

membrane is linked to create

a positive union.

Barriers fulfil two functions.

They trap rising gas and

prevent it from entering the

building envelope via the

cavity walls. They also arrest

downward penetrating

rainwater.

The combined use of

Petheleyne cavity barriers

and Type N sitesealer

membrane completes the

envelope integrity shield.

Gas arrested beneath the

integrity shield is discharged

via ventilation outlets.

The outlets are incorporated

below the oversite

membrane/barrier level.

Ventilators are the equivalent

size of a single brick and may

be easily introduced at

recommended centres and in

a colour to harmonize with

the masonry face.

On the top surface of the

barriers, collected water is

encouraged to discharge via

perp weeps. These are

incorporated at recommended

centres. The perp weeps are

of dual function, and promote

discharge of water whilst at

the same time encourage the

cavity wall to breathe.

(See Type W weepvents.)

The combined use of Type N

sitesealer membrane,

Petheleyne barriers,

appropriate ventilators and

cavity weepvents, results in a

protected building envelope

with passive extraction of gas

via the building perimeter

apertures. A gas reception

sump may also be

considered. Sumps are

classified as a secondary

protection method. The

reception sump receives gas

from underneath the building

and promotes passive

discharge via a vertical

ventilation stack.

The stack is terminated

above roof level.

construction oncontaminated land

High performance gas grademembranes to protect the site. (This is a primary protectionmethod.)

Compatible Petheleyne cavitybarriers to protect the cavities/cavitywalls and link with the oversitemembrane. (This is a primaryprotection method.)

Compatible reception sump toinhale gas and discharge viacompatible roof terminal outlet.(This is a secondary protectionmethod.)

Compatible ventilation outlets,breather discharge bricks andbarrier water weeps. (This is aprimary/secondary protectionmethod.)

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Type N SitesealerMembrane

for gas and damp-proofing

problemRequirement of a damp-

proofing membrane with

methane and radon resistant

qualities suitable for use on

oversite to seal against rising

gas. A medium also suitable

for specific tanking purposes.

introductionSolid concrete floors and

underground structures

require a damp-proof and

waterproof membrane to

adequately resist the

passage of moisture to the

inside of the building. In

addition, a membrane with

gas resistance is required

when construction takes

place on a methane emitting

site and/or a site subject to

radon gas building control

measures. Type N sitesealer

membrane is supplied for

such purposes.

solutionType N sitesealer gas grade

membrane was developed

from and is an enhanced

version of our original general

purpose membrane. It is of

multi-ply format, consisting of

a cross-orientated top layer or

polyethylene, laminated to a

bitumen polymer adhesive

base layer. A full width

aluminium primary integrity

barrier is sandwiched

between these materials.

The result is a gas resistant

membrane, offering

exceedingly low gas

permeability.

Type N sitesealer gas grade

membrane is supplied on a

carrier release paper, in rolls

of 30 sq. metres. Each roll

incorporates a lap-link edge,

to accommodate easy

alignment and lapping when

rolls are laid side by side.

Type N membrane is flexible

and serviceable when

subjected to stress movement

normally witnessed on site. It

will adhere to clean dry

surfaces, whilst surfaces that

are unsatisfactory because of

dust or porosity may be

primed using sitesealer

primer. At all times our

explicit instructions regarding

storage, handling and

application must be observed.

The membrane may be used

with our cavity barriers to

create a combined DPC and

gas integrity shield throughout

the walls and oversite of the

entire construction.

sizesStandard roll 28.6 metres x

1.05 metres x 1mm = 30 sq.

metres

Minimum recommended

overlaps:

Side 50mm

Ends 100mm

Sitesealer primer is available

in 25 litre cans. 1 litre covers

5 to 8 sq metres, depending

on porosity of surface.

Sitesealer linking/edging strip,

for intricate areas, lap and

patch purposes, reinforcing,

etc., is supplied in rolls 30

metres x 100mm width.

An optional protection board

to provide temporary cover to

laid membrane against site

traffic is available.

colourBitumen black.

service entry pointsA range of preformed

components are available for

use where services enter

through the membrane.

Termed Service Entry Points,

they provide a standardised

method of addressing

continuity of protection.

A typical example is shown

below.

installation/site workComprehensive installation

details are contained within

the original BBA certificate

and code of practice 102.

Instructions also accompany

every consignment and

should be studied prior to

use of the material.

Generally, surfaces receiving

sitesealer should be smooth

and free from projections,

deposits, cavities etc.

Unsatisfactory or damaged

surfaces must be made good

prior to the introduction of

membrane. Surfaces must

be frost-free, clean and dry.

• Seals against water transmission and gas transmission

• Cross-orientated ply construction

• Self-sealing bonding with lap-link edge

• Accompanying service entry accessories


The Type N sitesealermembrane (gas grade)was subjected to a radonmonitoring test. Thediffusion co-efficient insitesealer was reported asbeing less than 5 x (10-14m2s-1). The membranehas a very low permeabilityof methane and radon gasand has been formulatedto reduce the passage ofsuch gases on reclaimedor landfill sites and othergas emitting sites.When the British Board ofAgreement carried outtests on our Type Nwaterproofing membrane,they confirmed it satisfiesBuilding Regulations(England & Wales) C4, reg.7. Building Regulations(Scotland) 10 - B2.1 and17-G2.6. BuildingRegulations (NorthernIreland) B2 and C5.

technicalobservationsHigh resistance to waterpressure, water vapourtransmission and gastransmission.Cross-orientated plyconstruction.Self-seal bonding,eliminates joint heatingand drying.Branded with name andlogo as proof of type andaccompanying warranty.

Type N used with radon/methane (cavity) barriers.

Cavibricks discharge gas arrested under the barrier.

Caviweeps discharge penetrating water from the top of the barrier.

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Type N SitesealerMembranefor gas and damp-proofing

On porous surfaces or

surfaces which are

particularly dusty, sitesealer

primer should be used.

(Do not apply at

temperatures below 5°C.)

All vertical surfaces should

be primed when

encountered. Ensure

sufficient primer is used to

create a satisfactory surface

to receive membrane.

Any vertical or horizontal

loading should be applied

immediately after installation

to protect the membrane.

This action also resists

water/water vapour pressure.

Membranes must always be

protected.

bill of quantitywordingType N sitesealer membrane


Somerset BA22 8HU

(01935 474769). Install

membranes at appropriate

stage in accordance with

accompanying

instructions/standards.


details.

related products andapplicationsRefer to all products in this

section.

• Seals against water transmission and gas transmission

• Cross-orientated ply construction

• Self-sealing bonding with lap-link edge

• Accompanying service entry accessories

Type N used with radon/methane (cavity) barriers.

Sections show Type N membrane to oversite only andmethane / radon cavity barriers within cavity walls, lap jointed to provide continuous integrity.

TYPE N - GAS GRADE

Property Test Method Unit Data

DIMENSIONSBacking Thickness - mm 0.125

Backing Type - - Plastic / Aluminium

Laminate

Adhesive Thickness - mm 0.875

Total Thickness - mm 1.0

Width - mm 1050

Length - m 28.6

Weight - kg/m2 1.2

Carton Size - mm 260 x 260

1100

Carton Weight - kg 36

FUNCTIONAL DATAWater Vapour Transmission ASTM E96 g/m2/24h <0.01

Methane Gas Permeability Wimpey ml/m2/24h <0.03

Environmental

Est. Method

Radon Diffusion Permeability NRPB m2/s 5.0 10-14

Water Penetration Joint MOAT 27 5.1.4 % Nil

Dimension Stability

Longitudinal MOAT 27 5.1.6 % 0.0

(80°C)

Lateral 0.0

NOTE: The typical data shown in this leaflet is intended as a general guide and is based ontests carried out under controlled conditions.

ME

MB

RA

NE

Sphone

01935 474769 fax01935 428223 em

[email protected]

67

MethaneBarriers

for use within cavity walls

problemHow to create barriers for

installation in new-build

properties at ground floor

level designed to prevent

methane gas concentrations

accumulating.

introductionProperties are currently being

constructed on soil from

which methane gas is

emitted. Methane gas can

and has resulted in

explosion/fire and steps must

be taken to construct new

properties on methane

emitting ground in a manner

that controls this hazard and

permits safe discharge of the

dangerous gas.

solutionMethane barriers are

supplied in long lengths with

accompanying corners,

angles etc. The barriers are

incorporated within the cavity

wall at ground level. They rise

within the cavity and project

through the inside skin and

across the oversite. Oversite

membranes are also available

which seal to the perimeter

cavity mouldings. Thus, a

methane barrier is created

across the property floors

and walls, and methane gas

is prevented from

accumulating within the

structure.

Any methane gas which rises

is forced to discharge via

perimeter air bricks which

promote emission into the

open air and away from the

building. Methane barriers

use the same high void

format as radon barriers

which cross-ventilate

structures on all external

boundaries at the highest

possible level in relation to

the barrier position.

In selecting the appropriately

sized barrier to suit the cavity

construction, consideration

must also be given to the

rainwater which will

penetrate the external leaf of

the structure and upon

saturation produce volumes

of water on the inside face of

the external skin.

All barriers must arrest this

downward flow of moisture,

and discharge same through

weepvents.

We always recommend a

thorough survey of the site to

establish the existing and the

potential risk factors.

Her Majesty’s Inspectorate of

Pollution offer advice on the

matter of good design under

such circumstances.

sizesMethane barriers share the

same popular profiles as

radon barriers, (̀see page 78).

All dimensions can be varied

and we suggest we prepare a

schedule with our

recommendations. There is no

charge for this service.

Internal and external angles,

changes of level and drop-link

angles are manufactured to

match barrier profiles.

materialPetheleyne.

colourBlack.

installation/site workPerimeter barriers should be

bedded in mortar and

masonry bedded onto

barriers. Do not dry bed.

Ensure all adjoining lengths

and mouldings are sealed

using accompanying methane

sealing tape. Lap 150mm.

Ensure ventilation cavibricks

are incorporated and

positioned in accordance with

schedule. Ensure Type W

weepvents are installed at the

appropriate intervals on the

top face of the barrier in the

external skin. Oversite

membrane should be lapped

and sealed to provide airtight

junctions throughout.

Make sure all sections and

joins are made positively.

Create water-checks to top

face of barriers, where

specified. Read

accompanying instructions.

bill of quantitywordingMethane resistant barriers in

Petheleyne from Cavity Trays


8HU (01935 474769).

Install barriers at appropriate

stage in accordance with

accompanying

instructions/standards.


details.


section.

• Preformed cavity barrier lengths and angles

• Excellent gas resistance

• Compatible with oversite membrane

• Ensures regulation complianceThis style of methane barrier shows the barrier rising within the cavity and travelling across the horizontal oversite where it is lapped and sealedwith the oversite membrane.


“The gases which can affectthe occupants of buildingsinclude methane and carbondioxide. Methane is aflammable gas which formsan explosive mixture with airwhen the concentration isbetween 5 and 15% involume. A 1% concentrationsuggests that remedialmeasures are needed.Where carbon dioxide isalso present the range isnarrowed and when theproportion of carbon dioxidereaches 25%, methanebecomes non-flammable.Carbon dioxide hasasphyxiating properties. A5% concentration by volumesuggests that remedialmeasures are needed wherepeople will normally bepresent.”

See radon barriers forPetheleyne specification.See Type N sitesealer foroversite membrane.

technicalobservationsHigh void ventilation format.Gas resistant. Flexuouscomposition accommodatesminor structural movements.Provides waterbarrier/protection.Preformed to avoid siteerrors.Branded with name andlogo as proof of type andaccompanying warranty.

Rising gas is arrested anddischarged through cavibricks inthe external skin. Above thebarrier caviweeps dischargepenetrating water.

ME

MB

RA

NE

Sphone

01935 474769 fax01935 428223 em

[email protected]

68

Radon Barriers for use within cavity walls

problemHow to form cavity barriers

designed to minimise the entry

of radon gas into the building.

introductionRadon barriers function in

the same manner as

methane barriers.

They are installed in cavity

walls around the perimeter of

a structure. They are so

proportioned and shaped to

encourage rising radon gas

within the cavities to be

arrested and discharged via

brick ventilators appropriately

positioned.

The barriers extend through at

floor slab level and link with

the radon resistant oversite

membrane. The combined

use of cavity barriers and

oversite barriers minimise

radon entry into the building

envelope which would

otherwise take place. Thus,

levels are reduced within the

building and at all times

radon-laden air is promoted

to follow a discharge route

out of the structure, rather

than into it.

solutionIf construction is taking place

in an area subject to radon

emission or in an area in

which radon emission is

suspected, we recommend

barriers are always

incorporated. The local

authority should be consulted,

in the interests of health and

safety, and the possible future

liability of the designer and

contractor.

generalFor the successful treatment

of radon gas, it is necessary

to identify likely radon entry

routes and also undertake

appropriate work to a good

standard. The principle is to

prevent the rising gas from

entering the house.

Petheleyne barriers are

installed within all cavity

walls at floor slab level and

are linked to the oversite

membrane in a manner that

creates an integrity shield

across the entire property.

Stepped and staggered

properties require careful

attention to ensure integrity

in the horizontal, vertical and

stepped plane. Radon gas is

confined below the floor slab

level and vent discharged

where it quickly dilutes in the

outside air. Weepvents are

required at specified intervals

at barrier level, to facilitate

the discharge of rainwater

which penetrates the

external skin.

sizesStandard straight lengths

2.4m long.

Standard angles 450mm x

450mm.

Profiles shown are the most

commonly used, different

profiles are available.

Adjoining lengths and angles

should overlap by 150mm

minimum. Radon sealing

strip supplied in 30m rolls.

Calculation of total barrier

requirements should include

all angles, changes of level

and accompanying overlaps.

Petheleyne barriers are

provided in a variety of sizes

to accommodate horizontal

runs, corners, steps, vertical

links, party wall situations

with integral wall channels,

etc. We recommend

submission of drawings to

permit us to calculate/take-

off your requirements.

A quotation will then be

dispatched for your approval.

It is quite probable that your

requirements may be

supplied from some of our

stock sizes, and once familiar

with this system you may

care to calculate your own

requirements in the future.

However, our

quotation/processing service

is always available to you.

materialPetheleyne.

colourBlack.

bill of quantity wordingRadonbar the property.

Radon prevention barriers in

Petheleyne by Cavity Trays of


(01935 474769). Incorporate

Petheleyne radon prevention

barriers in accordance with


Observe good building practice

and wet bed all barriers in

accordance with codes of

practice regarding installation

of damp-proof courses. Ensure

all junctions between barrier

lengths and mouldings are well

lapped and sealed using radon

barrier sealing tape.


details.

• Preformed cavity barrier lengths and angles

• High-void gas ventilation

• Ensures regulation compliance in affected areasOversite barrier and cavity barrierlink to form safety shield.


The radon elementapplicable (chemical symbolRn and atomic number 86)is a group O gas. Occurringas three isotopes (219, 220and 222), it is formed whenthere is radioactive decay ofactinium, thorium anduranium. (Isotopescommonly known asactinon, thoron and radon.)Radon is classified as radon222 which is recognised asthe radiation danger inbuildings. Radon 222decays and produces aseries of decay products,often described as radon‘daughters’. Whilst radon222 is a gas, the decayproducts are technicallysolids which attach toparticles in the air as theyare formed. It is suchparticles that settle inbuildings and can enter thehuman lungs. Barriers andmembranes are intended toreduce the diffusion ofradon 222 gas from theground into the buildingenvelope. Whilst no barrieris completely impermeable,the use of barriers andconnecting oversitemembranes can reduce thelevel of radon gas ifcorrectly installed, withcareful attention given to alljoints, upstands, junctionsand links. A sample testanalysis of 1.5mmPetheleyne resulted inpermeability of less than 1.61012m2s1 (results quoted asratios of track counts).

Typical examples of angles thatcan be supplied in anydimensions to suit site andconstruction requirements.

ME

MB

RA

NE

S

69

problemDischarge routes for trapped

gases and trapped rainwater.

introductionThe use of membranes and

cavity barriers dictate the

installation of accompanying

measures to evacuate the

arrested gasses and arrested

rainwater out of the structure.

The examples shown are

described in detail on the

relevant product pages within

section 4. The purpose of

these entries is to highlight

aspects that must be

addressed as part of any

contaminated land gas

protection system. We will be

pleased to take off quantities

for any size of project and

submit a composite proposal

embracing all requirements.

solutionBrick-sized ventilator

available in many colours.

May be used at appropriate

centres beneath the radon or

methane barrier level to

promote discharge of trapped

gases. When servicing the

cavity, the cavibrick ventilator

is used without a sleeve.

Straight or cranked sleeves

are introduced to service

specific areas or voids. The

adjacent ground level must

be considered at all times.

type W weep ventand Euroweep-ventPerp weepvents for use on the

upper surface of the barrier

level. Both products when

used at the appropriate

centres promote evacuation of

penetrating rainwater arrested

at barrier level, whilst

simultaneously allowing the

cavity to breathe. Type W

weep/vents and Euroweep-

vents are dual-purpose and of

bi-pressure performance/

function. They should not be

confused with products which

do not offer this advantage.

service pipe entrypointsService pipe entry points or ‘top

hats’ as they are commonly

called, are fitted wherever a

service pipe penetrates the

oversite membrane. Their

purpose is to act as a gasket to

maintain gastight integrity.

Service pipe entry points are

available in a range of sizes to

suit all popular pipe dimensions.

Simply state pipe dimension to

order appropriate model.

• Compatible gas outlets

• Compatible water outlets

• Selection of colours

important note

Cavibricks must always beprovided on methaneemitting ground, but areclassified as secondaryprotection on radon emittingground. Site conditionsshould always be checked todetermine number ofcavibricks and frequency.Separate entries for theseproducts appear in therelevant sections.

When incorporated underthe petheleyne barrier level,the Cavibrick promotesexternal discharge of gases.Dotted line denotes positionof cavity barrier.

Air bricks sleeved to the under-floor void should be installed at1500mm centres. Straightsleeves, cranked sleeves andsleeve extensions accommodatevarying site levels andconstruction methods. Crossventilation of the structurepromotes evacuation. Air brickswithout sleeves service the cavityvoid (specify Cavibrick ventilatorin selected colour, withappropriate sleeves). Separatecavitray protection is not requiredwhen the Cavibrick is protectedadequately by the cavity barrier.

Cavibrick ventilator

Straight sleeve+integral cavitray

Cranked sleeve+integral cavitray

Sleeve + extension to cranked sleeve to accommodate large

step and height variations.

Rising gas is arrested belowthe oversite membrane andcavity barriers.

Service Pipe Entry Points approximate dimensions:

Base 350mm x 350mm - Height 150mm - to suit 25mm pipe.






Outlets and Entry Points gas and water discharge outlets

and incoming service pipes

phone01935 474769 fax


cavitytrays.co.uk

ME

MB

RA

NE

Sphone

01935 474769 fax01935 428223 em

[email protected]

70

Gas ReceptionSump

problemTo service evacuation of gas

from below integrity shield.

introductionThe gas reception sump

when positioned below a

floor slab (incorporating an

integrity shield in the form of

membranes and barriers),

provides a passive gas exit

route via a ventilation stack.

solutionThe gas reception sump is

designed to be incorporated

within the granular fill,

beneath the floor slab. The

reception sump receives gas

from underneath the building

and promotes passive

discharge via a vertical

110mm PVC ventilation stack.

The stack is terminated

above the roof finish with a

tile/slate external roof

ventilator.

Suitable for new-build or

existing properties, the

reception sump may service

up to 250m2 floor area,

positioned in the most central

location to promote

even/optimum evacuation.

The sump has integral

inhalation apertures and

inlet/outlet portholes to

permit spur connection to

adjoining sumps should the

size or layout of the property

dictate. A maximum of 5

reception sumps is permitted

per 110mm ventilation stack.

Where appropriate and if

necessary, mechanical

extraction can be achieved by

the introduction of a powered

fan, sited in the roof space.

Where sub-floor

depressurisation is created

using a gas reception sump,

it is recommended that the

sump should not influence an

area exceeding 250m2.

Sumps should be positioned

centrally and the serviced

area should not exceed a

distance from the sump of 15

metres. To promote maximum

depressurisation, fill used

underneath the slab around

the sump should not contain

excessive fines. In calculating

the performance of sub-floor

depressurisation, it is

assumed the water table is

not high and that any

measures to exhaust gases

will not be influenced by the

waterlogged/flooded areas.

sizesSump approximately 510mm

x 240mm plus porthole

projections which permit

connection to 110mm

standard vent/stack pipe.

Inhalation apertures exit ratio

exceeds 4 to 1 for optimum

performance. Roof tile

universal ventilator and roof

slate universal ventilator are

described elsewhere within

this manual.

bill of quantitywordingGas reception sump by Cavity


BA22 8HU (01935 474769).

Position sump centrally to

service area not exceeding

250 m2. Connect extraction

stack pipe. Spur connect

additional sumps to service

static pockets or sub-floor

areas as appropriate. Ensure

fill used around sump does

not include excessive fines.

Observe manufacturer’s


every delivery. Gas reception

sump total number = .....


details.


section.

• Passive or mechanical extraction

• Interconnection facility

• Permits use of standard pipe

• Compatible with others gas control products

In this example, the membrane is shownunder the oversite slab, rather than aboveit. Whichever option is selected to suit theconstruction in question, the outlet fromthe reception sump is always linked to themembrane using a service pipe flashing.

Both outlet options areillustrated. Vertical stack or up tofour horizontal connections arepossible. Thus gas evacuationcan be to perimeter walls ifappropriate, terminating withround converter and Cavibrick.

Each sump has four side connectionsand one top connection. This permitsinterconnection if a large area involvingmultiples of sumps is required.


NHBC 4.1-D5 stipulates adetailed investigation mustbe carried out when a site issuspected to havecontamination hazards.Radon gas is such a hazard.The cost of incorporating asump within the granular fillof a unit when constructing,is minimal. In Ireland it ismandatory for all newhouses to have a sump.

technicalobservationsInhalation/exist ratioexceeds 1:4.Single sump should notservice an area exceeding250m2.Single 100m pipe mayservice up to a maximum of5 sumps, arranged as fourspurs off main sump.

Further InformationAnalyses, May 1999.

James Long, The Benefits of

Cavity Trays. April 2000.

British Board of Agrement

BRE: GBG 33: Sept 1999.

BS5250.

BS5534.

BS6229.

BS5925.

NHBC Standards Extra (12)

1996.

GBG37 (Jan 2000) Insulating

roofs at rafter level.

IP1/00 (Jan 2000)

Airtightness.

GBG 60 (timber frame)

BS EN 772-11:2000.

BS EN 845.2 :2001

BRE IP 20/01.

NHBC Standards Extra April

2001, issue 21.

training video/building researchestablishment reportWe recommend close study

of the BRE report number 114,

issued by the Department of

the Environment. This excellent

unbiased report should be

read in conjunction with this

brochure. We also recommend

viewing of the training video,

produced by the Lead

Development Association (now

the Lead Sheet Association).

This video is called “Lead

Sheet Flashings” and

demonstrates the correct use

of leadwork in the industry.

Cavitrays manufactured by

Cavity Trays Limited of Yeovil

are the only recommended

proprietary systems within the

authoritative video.

resources audit In our 2004 Resources Audit,

97% of all waste was

identified as being recyclable

for use by other

manufacturers.

environmental Policy Statement Cavity Trays Ltd as a specialist

Company having recognised

responsibility for

further sources of information/referencesBuilding Regulations 1991.

Building Regulations 1995

update.

BS5628-3:2005.

BRE Digest 77.

BRE Digest 176.

BRE Digest 380.

BRE Digest 460, Part 1.

BRE Digest 460, Part 2.

NHBC Standards.

NHBC

Technical/Construction

Requirements.

NHBC Practice Note 5.

BRE Action Sheet 12.

BRE Action Sheet 36.

Code of Practice 121.

Lead Development

Association Guide to Good

Practice.

Lead Sheet Association

publication.

BRE Defect Action Sheet 98.


BRE Defect Action Sheet

108.


BRE Digest 333.

BRE Digest 364.

BRE Digest 380.



Zurich Insurances Technical

Manual.

BRE Defect Action Sheet

120.

BRE Digest 270.

BRE Digest 297.

BRE Radon, - Guidance on

protective measures to new

buildings.

BRE, Thermal Insulation,

avoiding risks.

BRE 227.

BS5250.

BS6093.

BS8000.

BS8215.

BS8298.

BS493.

BS5977.

BRE GBG 25.

Thermal Insulation:

Avoiding Risks (1994 update).

James Long, Cavity Tray

environmental matters places

a high priority on

environmental affairs with

regard to Company operations

and the supporting services

offered to customers.

The need for environmental

protection forms an integral

part of Cavity Trays business

philosophy. Our activities and

those of our employees have

an effect on the environment.

We endeavour to operate in

harmony with the relevant

environmental laws and

regulations applicable in each

country in which we operate

and work with regulatory

agencies and advisers as

required. (A copy of our full

Environmental Statement is

available upon request).

performanceguaranteeCavity Trays Ltd is not able to

make any warranty under this

guarantee as to the standards

of workmanship with which

products are incorporated.

This guarantee sets out fully the

rights of the party to whom it is

granted. This guarantee does

not extend to any other losses,

howsoever arising. The

guarantee is not assignable.

Not covered in our guarantee:

Water entry damage via or

around a material or fitting not

supplied by Cavity Trays Ltd.

Any problem arising through

failure of mortar.

Any change in colour or

appearance.

Misuse of product.

Damage by lightning, pollution,

movement or resulting from

weather conditions more severe

than average or occurring

infrequently.

Movement or subsidence.

Incorrect installation.

Use of incompatible materials.

The gurantee applies only to

correctly specified, dimensioned

and manufactured goods

installed in accordance with our

fitting instructions.

Cavity Trays Ltd guarantees

the functionality of correctly

installed cavitrays for a period

of twenty years. Following

settlement in full the date of

our original supply invoice is

the date from which any

period is calculated. Cavity

Trays Ltd will pay the cost to

bring the performance of the

specific units only proven to

have failed into functionality

status but not further or

otherwise. The amount

payable shall not under any

circumstances exceed the

original net supply cost of the

specific units only, to which a

labour only figure be added,

based on a multiple of the net

goods value, in accordance

with our gurantee schedule.

We do not undertake to pay

any other damages arising

from non-performance,

including (but not limited to)

the costs of damage to the

building contents, damage to

the building structure and

liquidated damages.

Our liability extends only to

the specifications based on

information provided prior

to our design work

commencing and excludes any

liability arising out of incorrect,

inaccurate or incomplete

information supplied by any

involved party to Cavity Trays

Ltd.

building regulationsThe Building Regulations may

be satisfied with use of our

products and systems. We

recommend study of the

Technical Observations and

Considerations which appear

alongside every product. In

many instances the standards

offered are unmatched by any

other organisation.

orderingProducts may be ordered

from your local Builders

Merchant. Many merchants

hold stocks of our goods, and

we will be pleased to issue

stockist names upon request

via telephone or fax.

Alternatively, you may place

instructions with our sales

offices direct by telephoning

01935 474769.

If you adopt this procedure,

it permits us to advise on

availability and to arrange for

the goods to be supplied

through the merchant

appropriate to your area.

sources ofinformation/conformityCurrent Building Regulations,

SSHA, LSA Recommended

Guidelines, NIHE, GLC

Approval Bulletin, PBA, NBS,

Wimpey Laboratories, Quality

Assurance Scheme, Code of

Practice, NFRC Technical

Bulletin, National Building

Specification, NHBC

Standards, Lead Sheet

Association, ELSIA European

Lead Sheet Industry

Association.

material standardsStainless Steel BS1149,

Type 304/318, Austenitic.

Moulding Polypropylene.

Manufacturing to a quality

system approved to BSEN

ISO 9001: 2008.

Galvanised steel BS2989.

Copper BS2870.

Aluminium BS1470.

Petheleyne Grade AA.

BS5139. BS10143.

Lead BES EN 12588: 1999.

BS476: Pt 3, (fire tests of

specified products). BS EN

10142: 1991. BS3900.

The new British Standard

5628-3:2005 introduced a

new code of practice for use

of masonry, part 3 covering

materials and components,

design and workmanship.

The trays illustrated within the

new standard are available

from Cavity Trays of Yeovil.

Cavity Trays of Yeovil holds

LABC Product Type Approval.

In 1920 a West Country family ofbuilders started making their owndamp courses, flashings and cavitrays,the fourth generation of the samefamily continue the tradition.

The Company is now called CavityTrays Limited and can claim moreexperience, more case histories andmore know-how than any othercompany in this specialised field.Approved cavitrays with Agrémentcertificates are manufactured to a

quality management systemconforming to BSEN ISO 9001: 2008. Cavitrays have high performancecategorisation and are accompaniedwith product liability. This importantbenefit is offered as standard when youuse Cavity Trays Limited. It provides aschedule of protection.

Enjoy the benefit of four generations ofexperience and proven performance,by clearly specifying Cavity TraysLimited of Yeovil.

enjoy the benefit of fourgenerations of experience

Cavity Trays LimitedAdministration CentreYeovil SomersetBA22 8HU EnglandTelephone 01935 474769Facsimile 01935 428223www.cavitytrays.com

Log onto www.cavitytrays.com to access the latest productinformation. Data sheets, product specifications, CAD downloadsand video demonstrations showing how products are used.

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