PRODUCT DESCRIPTIONThis Certificate relates to Permo Forte Roof Ti leUnderlay, which is a spunbonded polypropylene fabricunderlay for use in slated or tiled pitched roofs.

USE:Permo Forte Roof Tile Underlay is manufactured for useunder slates or tiles on open rafter (unsupported) orfully supported pitched roofs. The underlay may beused in the following roof systems:1. Conventional cold roof system 2. Non-ventilated in a cold roof system3. Ventilated in a warm roof system 4. Non-ventilated in a warm roof system.

The installation of these roof systems using Permo ForteRoof Tile Underlay is described in Section 2.4 of thiscertificate.

Permo Forte Roof Tile Underlay provides a barrierwhich:● Prevents the ingress of wind-blown rain, dust and

snow.

● Minimises the wind load generated under wind gustsacting on slates and ti les when instal led inaccordance with this certificate.

● Offers super ior resistance to tear ing dur inginstallation.

● Remains flexible at low ambient temperatures.● Faci l itates the control of harmful sur face and

interstitial condensation in the roof by allowing thesafe dispersal of water vapour, when installed inaccordance with this certificate.

This Certificate is a confirmation of BBA Certificate No.00/3749 Permo For te Roof Ti le Underlay in non-ventilated cold pitched roof systems (2nd issue) issuedby the Br itish Board of Agrément, PO Box 195,Bucknalls Lane, Garston, Watford, Herts., WD25 9BA

MANUFACTUREThe product is manufactured by:

Klober GmbH & CoScharpenberger Str. 72-90D-58256 Ennepetal, Germany

IRISHAGRÉMENT

BOARDBUILDING PRODUCT CERTIFICATION

CERTIFICATE No. 03/0190

(47) Ln6

Cl/SfB

Klober Limited, Ingleberry Road, Shepshed, Loughborough,Leicestershire LE12 9DE, United Kingdom

Tel: 0044 1509 500660 Fax: 0044 1509 600061

Permo Forte Roof Tile Underlay in ventilated andnon-ventilated pitched roof systems

Souscouche de couverture en ardoises où en tuilesUnterlage für Schieferdach oder Ziegeldach

The Irish Agrément Board is designated by Government to issue European Technical Approvals.

Irish Agrément Board Certificates establish proof that the certified products are ‘proper materials’ suitable for their intended use under Irish site conditions, and in accordance with the Building Regulations 1997 to 2002.

The Irish Agrément Board operates in association withthe National Standards Authority of Ireland (NSAI) as the National Member of UEAtc.

Readers are advised to check that this Certificate has not been withdrawn or superseded by a later issue by contacting:Irish Agrément Board, NSAI, Glasnevin, Dublin 9

MARKETING

The product is marketed by:

Klober LtdIngleberry Road, Shepshed, LoughboroughLeicestershire, UKTel: 00 44 1509 500660Fax: 00 44 1509 600061

and

Capco Roofing CentreUnit 47/48 Broomhill Close, TallaghtDublin 24Tel 00 353 (0)1 4620740Fax: 00 353 (0)1 4620741

CERTIFICATION

PAR

T 11.1 ASSESSMENTIn the opinion of the Irish Agrément Board (IAB), PermoForte Roof Tile Underlay is satisfactory for the purposedefined above, and meets the requirements of theBuilding Regulations 1997 to 2002 as indicated inSection 1.2 of this certificate.

1.2 BUILDING REGULATIONS 1997 to 2002

REQUIREMENT:

Part D - Materials and Workmanship

D3 - Permo Forte Roof Tile Underlay, as certified in thisIrish Agrément Board (IAB) certificate, is a propermaterial, fit for its intended use (see Part 4 of thiscertificate).D1 - Permo For te Roof Ti le Underlay, used inaccordance with this Ir ish Agrément Board (IAB)certificate, meets the requirements for materials andworkmanship.

Part A – Structure

A1 - Loading Tests indicate that a roof incorporating Permo ForteRoof Tile Underlay meets the requirements provided theinstallation complies with the conditions set out inSection 2.4 and Part 3 of this Irish Agrément Board(IAB) certificate.

Part B – Fire Safety

B4 - External Fire Spread Permo Forte Roof Tile Underlay will not prejudice theexternal fire resistance of the roof, as indicated inSection 4.1 of th is Ir ish Agrément Board (IAB)certificate.

Part C – Site Preparation and Resistance toMoisture.

C4 - Resistance to Weather and Ground MoisturePermo Forte Roof Tile Underlay meets the requirementswhen installed as indicated in Section 2.4 of this IrishAgrément Board (IAB) certificate.

Part F – Ventilation

F2 - Condensation in Roofs

Permo Forte Roof Tile Underlay wil l provide watervapour permeabil ity in excess of that quoted as aminimum for a vapour permeable underlay in I.C.P. 2:2002 Irish Code of Practice for slating and tiling andhence, movement of moisture vapour can take placethrough the underlay.

The design guidelines contained in the Section 2 of theTechnical Guidance Document to Part F of the BuildingRegulations 1997 to 2002 and in Section 8.4 of BS 5250:2002 Code of Practice for control of condensation inbuildings, must be met.

In a non-ventilated roof system where Permo Forte RoofTile Underlay is installed in accordance with this IrishAgrément Board (IAB) certificate, the underlay canprevent excessive condensation in a roof or in a roofvoid above an insulated ceiling as is required by Part Fof the Building Regulations 1997 to 2002.

Permo Forte Roof Tile Underlay can be treated as avapour permeable underlay when considering theventilation requirements of the roof.

Part L - Conservation of Fuel and Energy

L1 - Conservation of Fuel and EnergyBased on the measured vapour resistance of PermoForte Roof Tile Underlay, roofs incorporating insulationcan meet the requirements of Part L of the BuildingRegulations 1997 to 2002.

Where the Permo Forte Roof Tile Underlay is installedwith ventilation and the ceiling has to be fixed to thesoffit of the rafters, as in dormer roof construction,ventilation should be arranged for as shown in diagram6D of TGD to Part F of the Building Regulations 1997 to2002; in these circumstances it will be necessary toinstall a vapour control layer at the warm side of theinsulation.

In a non-ventilated roof system where Permo Forte RoofTile Underlay is installed in accordance with this IrishAgrément Board (IAB) certificate and manufacturer'sinstructions and the ceiling has to be fixed to the soffitof the rafters as in dormer roof construction, it is likelyto be necessary to install a vapour control layer at thewarm side of the insulation.

2.1 PRODUCT DESCRIPTIONPermo Forte Roof Tile Underlay is a watertight, vapourpermeable, f lexible underlay intended for use as anunsupported/supported underlay beneath slates or tiles,constructed in accordance with I.C.P. 2: 2002 Irish Codeof Practice for slating and tiling.

2.2 MANUFACTUREPermo For te Roof Ti le Underlay is a four layerconstruction, comprising two spunbondedpolypropylene fabric layers and a polypropylene meshfused together around a microporous plastic film. Theupper layer of the underlay is light grey in colour andthe lower layer is white

The physical characteristics of Permo Forte Roof TileUnderlay are given in Table 1.

2.2.1 Ancillary ItemsAncillary items available areButylon – butyl adhesive tapeTacto – double-sided adhesive tapeFlecto – single-sided adhesive tapeKlober Eaves Carrier – a uPVC detail used to protect theedge of the underlay from the effects of ultra-violet lightageing and as a run-off into the gutter

2.2.2 Quality ControlQuality control checks are carried out on the incomingraw materials, during production and on the finishedproduct. Qual ity control checks include v isualinspection and checks on roll and membrane weights,dimensions (length, width, thickness), tensile strength,tear resistance, water vapour permeability and waterpenetration resistance (hydrostatic head).

2.3 DELIVERY, STORAGE AND MARKINGPermo Forte Roof Tile Underlay is supplied in 50-metrerolls, shrink-wrapped in polythene with a label bearingthe company name and the product name

Rolls should be stored on their sides on a smooth,clean, dry surface and be kept under cover to protectfrom long-term exposure to UV light. Care must betaken to avoid contact with solvents and with materialscontaining volatile organic components such as coal tar,and timbers newly treated with creosote.

The rolls must not be exposed to a naked flame or otherignition sources.

Table 1Physical Characteristics of Permo Forte

Roof Tile Underlay

2.4 INSTALLATION PROCEDURE

2.4.1 GeneralPermo Forte Roof Tile Underlay must be installed andfixed in accordance with th is certificate and themanufacturer's/distributor’s instructions, a copy ofwhich should accompany each rol l, and therecommendations of I.C.P. 2: 2002 Code of Practice forslating and tiling.

2.4.2 InstallationInstallation of Permo Forte Roof Tile Underlay can becarried out in all conditions normal to pitched roofingwork. In roof construction it is important to rememberthat Permo Forte Roof Tile Underlay is the second lineof defence in excluding water penetrating the roof. Forthis reason the following list of criteria must be met tocomply with the requirements of this certificate.

2.4.2.1 General installation criteria for PermoForte:

● Where the length of the roof slope measured on planexceeds 6m, Permo Forte Roof Tile Underlay should onlybe used if slate or tile manufacturer’s guidance is soughton detailing.

● Ensure that Permo Forte Roof Tile Underlay is laid parallelto the eaves with the light grey side and product nameuppermost, and not damaged.

● Where Permo Forte Roof Tile Underlay becomes damagedfor whatever reason, it is imperative that it is suitably

Material SpunbondPolypropylene, LLDPE

Colour Light grey, upper surfaceWhite, lower surface

Roll Width (m) 1.5Roll Length (m) 50Roll Weight (kg) 14Thickness (mm) 0.68

Water Vapour Resistance 0.2(MNs/g)

Water Vapour Permeability – Temperate Climate (g/m2/day) 1034Hydrostatic Head (mm of H2O) >1500

Resistance to wind load (Kpa) 2.5 with 300mm battenspacing and 600mm raftercentres

Tensile Strength (N/50mm) MD 386 ± 10%CD 262 ± 10%

Tensile Elongation (%) MD 15%CD 16%

Tear Resistance (N) MD 190CD 122

TECHNICAL SPECIFICATION AND CONTROL DATAPA

RT 2

repaired with a new piece of the same material or, if thedamage is only minor, with Klober Flecto adhesive tape.All penetrations to the underlay, such as vent pipes andchimneys should also be sealed with Klober Flectoadhesive tape to ensure complete protection of theinterior.

● It is imperative that persons working on the roof do notuse the underlay for supporting themselves or theslates/tiles independently of the roof.

● Overlaps of the underlay should be prov ided inaccordance with the minimum dimensions given in Table2, which are taken from I.C.P. 2: 2002 Irish Code ofPractice for slating and tiling.

● Where underlay overlaps do not coincide with a batten,consideration should be given to either including an extrabatten at the overlap or increasing the underlay overlap tocoincide with the next batten.

● Batten gauges should not exceed that recommended bythe tile/slate manufacturer for the particular tile/slatebeing used.

● Moisture content of battens at time of fixing should notexceed 22%.

● Where timbers on roofs are to be treated with woodpreservative, it is essential that manufacturer's guidancebe sought in relation to possible chemical attack on theroofing underlay.

● When tack ing roof underlay to the raf ters it isrecommended that a 3mm diameter X 20mm long extralarge head clout/felt nails of copper, aluminium alloy orgalvanised steel be used. The underlay should be tackedat the head of the sheet only, at centres not exceeding1200mm. It is important that all tacking nails be coveredby the overlap of the next underlay course. Where hipsand valleys occur on roofs, lay an additional strip ofunderlay at least 600mm wide, running continuously fromeaves to ridge.

● For duo pitch roofs not requiring ridge ventilation,underlay from each side of the ridge should overlap theother side by at least 225mm. Where propr ietaryventilating ridge systems are specified, detailing of theunderlay should be in accordance with the manufacturer’srecommendations.

● Where used unsupported, the underlay should be drapedwith a deflection of approximately 10mm between raftersto permit free drainage of water into the gutter.

● Where used fully supported on decking or insulation,counterbattens should be used and the guidelines fromBS 5250:2002 should be followed.

● Once Permo Forte Roof Tile Underlay is installed, itshould not be exposed to UV light for more than fourmonths as it will degrade if exposed long-term to UVlight. At the eaves a Klober Eaves Carrier UV-light-resistant underlay support tray or equivalent protectionmust be installed onto which the underlay can be lappedand sealed with Klober Tacto Double Sided tape.

● Permo Forte Roof Tile Underlay is not suitable for use inflat roof construction.

● Figure 1 shows Permo Forte installed on a non-ventilatedcold roof structure. Figure 2 shows Permo Forte installedon a non-ventilated warm roof structure.

2.4.2.2 Installation Criteria for Non-ventilatedroof designs in relation to condensation risk.The Permo Forte Roof Tile Underlay has a significantlyh igher water vapour permeabi l ity than that ofconventional roof underlay and therefore does not haveto rely upon air movement beneath the underlay tominimise the risk of damage through condensation.However it is essential that the amount of water vapourgenerated in the dwel l ing below is l imited. Thefollowing measures will help to reduce the build up ofwater vapour.● All penetrations into the roof space must be properly

sealed and loft hatches made convection tight bymeans of a compressible draught seal.

● The dwelling below the roof must be ventilated inaccordance with section F1 of TGD to Part F of theBuilding Regulations 1997 to 2002 for the dispersaland rapid dilution of water vapour.

● All water tanks in the loft space must be covered andall pipe work lagged.

● Extractor fans must be used in rooms that mayexperience high humidity, such as kitchens, utilityrooms and bathrooms. The ventilation rates of thefans should be in accordance with the BuildingRegulations 1997 to 2002.

● A vapour control layer should be installed on thewarm side of the insulation in both cold roof designsand warm roof designs.

● All penetrations, e.g. pipe work, electrical fittings tothe loft space must be sealed.

To allow water vapour to disperse above the underlay,counter battens and ti l ing battens of minimumthickness 25mm each should be used where the spacebeneath the underlay is not ventilated. This airspace isopen to the atmosphere, between the roof covering andthe underlay and no eaves or r idge venti lation isrequi red. As the venti lation of th is ai rspace isdependent on gaps between the tiles or slates it maynot be adequate where these are tightly jointed. In thiscase full ventilation (at eaves and ridge) of this airspacemay be required.

The insulation is laid horizontally on a vapour barrier atceiling level and must be pushed into the eaves andagainst the underlay to ensure that there are no gapspresent.

Roof Pitch Horizontal lap (mm) Vertical lap (mm)

Partially Supported Fully Supported

Pitch<22.5° 225 150 100

22.5°<pitch<35° 150 100 100

Pitch>35° 100 75 100

Table 2. Minimum Overlaps (According to I.C.P. 2: 2002)

Fig. 1 Permo Forte installed on a non-ventilatedcold roof structure

Fig. 2 Permo Forte installed on a non-ventilatedwarm roof structure

3 GENERAL3.1 Permo For te Roof Ti le Underlay prov ides asatisfactory underlay in slated and tiled pitched roofsconstructed in accordance with I.C.P. 2: 2002 Irish Codeof practice for slating and tiling.

3.2 STRENGTHPermo Forte Roof Tile Underlay will resist the loadsassociated with the installation phase of the roof.

Permo Forte Roof Tile Underlay has adequate resistanceto wind uplift forces in most locations in Ireland.

3.3 WEATHERTIGHTNESSTests confirm that Permo Forte Roof Tile Underlay willresist the passage of water and wind-blown snow anddust into the interior of a building under all conditionsto be found in a roof constructed to I.C.P. 2: 2002 IrishCode of practice for slating and tiling.

The underlay may be used to prov ide temporarywaterproofing to the structure of the building prior tothe instal lation of slates or ti les. It is howeverrecommended that this period of time be kept to aminimum in accordance with the manufacturer’sguidance.

3.4 VENTILATIONWhere Permo Forte Roof Tile Underlay is installed withventilation, particular attention should be given to

ensure that there is adequate ventilation to the roofspace at eaves and where required at ridge levels inaccordance with Part F of the Building Regulations 1997to 2002. Ridge vents must be flashed and sealed to theunderlay to ensure that the roof space is ventilated at alltimes.

In conventional ventilated roof systems where theceiling has to be fixed to the soffit of the rafters andinsulation is fitted between rafters, as in dormer roofconstruction, a continuous ventilation space of at least50mm should be arranged for as shown in Diagram 6Dof TGD to Part F of the Building Regulations 1997 to2002; in these circumstances it will be necessary toinstall a vapour control layer at the warm side of theinsulation.

Where Permo Forte Roof Tile Underlay is installed in anon-ventilated cold or warm roof system, the risk ofcondensation is equivalent to, or less than, that forconventionally ventilated cold roof systems meeting thecriteria of BS 5250: 2002 Code of Practice for control ofcondensation in buildings.

It is essential that roofs be constructed so as tominimise the risk of moisture vapour entering the atticspace and forming condensation. In accordance withgood building construction practice, all openings forservices and trap doors should be draught sealed, andtrap doors should not be located in bathrooms, showerrooms or kitchens.

DESIGN DATAPA

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TECHNICAL INVESTIGATIONS4PAR

T

4.1 BEHAVIOUR IN FIREPermo Forte Roof Tile Underlay has a class B2 firerating, with similar properties in relation to fire astraditional underlays, and so will present no additionalf i re hazard to a roof structure in which it isincorporated.

Tests indicate that there is a risk of fire spread if PermoForte Roof Tile Underlay is accidentally ignited duringmaintenance works, etc. (e.g. by a roofer or plumber’storch). As with all types of sarking material, care mustbe taken during building and maintenance to avoid thematerial becoming ignited. It should not come incontact with hot chimney surfaces as per clauses 2.15to 2.17 of the TGD to Part J of the Building Regulations1997 to 2002

Toxicity is negl igible when used for a roofingapplication.

4.2 WATER PENETRATIONPermo For te Roof Ti le Underlay, when used inaccordance with this certificate, presents no significantrisk of water penetration.

4.3 WATER VAPOUR PENETRATION ANDCONDENSATION RISK

Permo Forte Roof Tile Underlay has a significantlyhigher water vapour permeability than that quoted as aminimum for conventional roof underlays in I.C.P. 2:2002 Irish Code of practice for slating and tiling and,hence, movement of moisture vapour can take placethrough the underlay.

4.4 DURABILITY AND MAINTENANCEPermo Forte roof underlay, once installed in accordancewith this certificate, manufacturer's instructions andrelevant codes of practice is virtually unaffected byconditions normally found in a roof space and will havea design life comparable with that of the roof and inaccordance with BS 7543: 1992 Guide to the durabilityof building elements, products and components. Thedurability of the roof underlay will be dependent on theperformance of the roof covering (slates/tiles) and thiscould be compromised if the roof is not routinelymaintained or is subjected to inappropriate traffic.

Such maintenance would involve building ownershaving their roofs inspected annually, preferably in late

5.1 CONDITIONS OF CERTIFICATIONThe National Standards Authority of Ireland (“NSAI”)following consultation with the Irish Agrément Board(“IAB”) has assessed the performance and method ofinstallation of the system and the quality of thematerials used in its manufacture and certifies thesystem to be fit for the use for which it is certifiedprovided that it is manufactured, installed, used andmaintained in accordance with the descriptions andspecifications set out in this certificate and inaccordance with the manufacturer’s instructions andusual trade practice. This certificate shall remainvalid so long as:(a) the specification of the product is unchanged;(b) the Building Regulations, 1997 to 2002 and any

other regulation or standard applicable to theproduct/process/system, its use or installationremain unchanged;

(c) the product continues to be assessed for thequality of its manufacture and marking by NSAI;

(d) no new information becomes available, which inthe opinion of the NSAI would preclude thegranting of the certificate;

(e) the system continues to be manufactured, installed,used and maintained in accordance with thedescr iption, specif ications and safetyrecommendations set out in this certificate.

5.2 The IAB mark and certification number may only beused on or in relation to the system in respect of whicha valid certificate exists. If the certificate becomesinvalid, the certificate holder must not use the IAB markand certification number and must remove them fromproducts already marked.

5.3 In granting this certificate, the NSAI makes norepresentation as to:

(a) the presence or absence of patent r ightssubsisting in the product/process/system; or

(b) the legal r ight of the certificate holder tomarket, instal l or maintain the product/process/system; or

(c) whether indiv idual products have beenmanufactured or installed by the certificateholder in accordance with the descriptions andspecifications set out in this certificate.

5.4 This cer tif icate does not comprise instal lationinstructions and does not replace the manufacturer’sdirections or any professional or trade advice relatingto use and installation which may be appropriate.

5.5 Any recommendations contained in this certificaterelating to the safe use of the certified product orprocess are preconditions to the val idity of thecertificate. However, the NSAI does not certify thatthe manufacture or installation of the certified productor process in accordance with the descriptions andspecifications set out in this certificate will satisfy therequirements of the Safety, Health and Welfare atWork Act, 1989 or of any other current or futurestatute or current or future common law duty of careowed by the manufacturer or by the certificate holder.

5.6 The NSAI is not responsible to any person or body for lossor damage, including personal injury, arising as a direct orindirect result of the use of this product or process.

5.7 Where reference is made in this certificate to anyAct of the Oireachtas, regulation made thereunder,statutory instrument, code of practice, nationalstandards, manufacturer’s instructions or similarpublication, it shall be construed as reference tosuch publication in the form in which it is in forceat the date of this certification.

CONDITIONS

PAR

T 5

autumn. Inspection should include check ing formissing, damaged or loose slates/ti les and thei raccessories or flashings. Clogged gutters or down pipesshould be unblocked and cleaned.

4.5 TESTS AND ASSESSMENTS WERE CARRIEDOUT TO DETERMINE THE FOLLOWING:

● Water penetration resistance● Water vapour resistance● Water vapour permeability● Wind Resistance● Tensile strength● Tear strength● Dimensional accuracy● Dimensional stability● Efficiency of the construction process

4.6 OTHER INVESTIGATIONS● Existing data on product properties in relation to fire,

toxicity, environmental impact and the effect onmechanical strength/stability and durability wereassessed.

● The manufacturing process was examined includingthe methods adopted for quality control, and detailswere obtained of the quality and composition of thematerials used.

● Site visits were conducted to assess the adequacy ofstorage practices and the practicability of installationand the history of performance in use of the product.

● Driving rain resistance was assessed.● A condensation risk analysis was performed.

THE IRISH AGRÉMENT BOARD

This Certificate No.03/0190 is accordingly granted bythe NSAI on behalf of The Irish Agrément Board toKlober Limited.

Date of Issue: September 2003

Signed:

Chief Executive, NSAI

Readers may check that the status of this Certificatehas not changed by contacting the Irish AgrémentBoard, NSAI, Glasnevin, Dublin 9. Ireland.

Telephone: (01) 807 3800.Telefax: (01) 807 3842.www.nsai.ie

IRISHAGRÉMENT

BOARDBUILDING PRODUCT CERTIFICATION

Irish Agrément BoardNSAIGlasnevinDublin 9IrelandTelephone: (01) 807 3800Telefax: (01) 807 3842