One of the objectives of the CSSBI and its members isthe development of standards and technicalpublications that promote safety, performance andgood practice. This "How To Series" of publications isan educational tool intended to give guidance toanyone specifying sheet steel building products. Thisparticular publication is published as an aid to buildingowners as well as roofing and siding installers. It offerssimple and practical recommendations for theselection, application and installation of lightgaugesteel cladding.
This is a generic guide giving the basic details andshould only supplement the specific recommendationsor guidance published by the manufacturer appropriateto their own products. The views expressed in thisguide are a collection of installation techniques and donot necessarily reflect those of all member companiesof the CANADIAN SHEET STEEL BUILDINGINSTITUTE.
The material presented in this publication has beenprepared for the general information of the reader.While the material is believed to be technically correctand in accordance with recognized good practice at thetime of publication, it should not be used without firstsecuring competent advice with respect to its suitabilityfor any specific application. Neither the CANADIANSHEET STEEL BUILDING INSTITUTE nor itsMembers warrant or assume liability for the suitabilityof this bulletin for any general or particularapplication.
Lightgauge steel roofing and siding (referred to as“cladding”) is used as the covering on many buildings,often over wood frame structures in agriculturalapplications. The use of these products, however, isextending more into light commercial projects where thebenefits of the lightgauge products are also beingutilized. The appearance and service life of the steelroofing and siding can be enhanced by following properinstallation procedures as described in this guide.
This guide assumes that the building structure is suitablyengineered and that the building is square. Foragricultural applications, the Canadian Farm BuildingHandbook published by the Research Branch ofAgriculture Canada and the Construction Guide for FarmBuildings published by the Ontario Housing andBuilding Development Branch are available asreferences. Light commercial and industrial buildingsmust be designed by a professional engineer or architect.Buildings that use lightgauge steel roofing and sidingmust comply with all relevant aspects of the applicableProvincial and local Municipal building codes. Allinstallations require approval by the appropriatebuilding official.
This publication deals with the selectionand installation of lightgauge sheet steelcladding in single skin applications (i.e.without an interior liner sheet orinsulation). For information on insulatedsheet steel assemblies, consult theCSSBI publication S10-1997, How ToSeries: Insulated Sheet Steel WallAssemblies and S11-2000, How ToSeries: Insulated Sheet Steel RoofAssemblies.
Please read this guide completely beforebeginning any installation. Planning nowcan save a lot of time and effort later.
Why Use Lightgauge SHEET STEEL PRODUCTS
Sheet steel is a material that is exceptionally durable, yethas the versatility to fulfil the most demanding andinnovative designs.
Prepainted sheet steel is versatile. It is available in awide range of thicknesses and profile shapes. It is easilyintegrated with other building materials and can bemanufactured to meet the loading requirements of any
building.
Prepainted sheet steel isdurable. Coating systemshave been developed andproven over the past 35years in a diverse range ofenvironmental conditions.Prepainted sheet steel hasbeen successfullyincorporated intonumerous types ofstructures across North
America, from the extreme climatic fluctuations of theprairies, to the highly corrosive environments of heavyindustry, to severe conditions in coastal maritimelocations.
Prepainted sheet steel is colourful. A rainbow ofpossibilities allows creative opportunities to designprojects with a palette of colours as diverse as theimagination. The choices are virtually limitless,providing the ability to design colour into a building soit stands out on the horizon or blends into theneighbourhood. Corporate colours can be matched toestablish a client’s image, or just a touch of colour canbe added to heighten the aesthetics of the project.
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Prepainted sheet steel is economical. It offers theeconomies of a lightweight roll formed product allowingstructures to be designed using economical componentswith the added advantage of having the flexibility ofincorporating efficient insulation packages into thebuilding envelope. Thanks to the versatility and range ofquality prefinished sheet steel profiles, there are panelsystems available to accommodate any budget.
Material Selection
All lightgauge sheet steel building products have onething in common: they are fabricated from metalliccoated, quality controlled, sheet steel. This material canalso be prepainted for additional corrosion protectionand enhanced aesthetics. Each component of the steelsheet (steel core, metallic coating, and organic coating)is important to the service life of the finished product.There is a range of steel properties and coatings thatprovide flexibility in specifying the appropriate material.It is important to select the coatings to suit theanticipated environmental conditions and budget.
Steel Core: A sheet steel cladding profile is anengineered product and must be manufactured fromsheet steel with certified structural properties. The datasheets available from the manufacturer will list therelevant material specifications and allowable spans.The steel core of the sheet is available in a range ofthicknesses and strength levels to accommodate varyingstructural requirements.
Metallic Coatings: It is important that corrosion of thesteel be minimized and not allowed to affect thestructural integrity and aesthetics of the product;
therefore, the steel core must be separated from theenvironment. The first line of protection for the steel issupplied by the metallic coating, one of the mosteffective methods of protecting bare steel fromcorrosion. Both zinc and aluminum-zinc alloy coatingsprovide a tough, non-porous metallic coating that doesnot allow moisture to come in contact with the steel.
Besides acting as aprotective barrier,the metallic coatingis able to "sacrifice"itself to protect theunderlying sheetsteel if both metalsare exposed, like ata cut edge or ascratch. Sacrificialprotection occurswhen twodissimilar metalsare in electricalcontact and arecoupled with waterand oxygen. Undermost conditions,zinc can protectexposed steel or cut
edges up to 1/16 inch in width. A more in-depthdescription of the "sacrificial" protection process can befound in many engineering materials handbooks.
The aluminum-zinc alloy coating also provides similarsacrificial and barrier type protection of the steel, asdescribed above. Aluminum-zinc alloy coated sheets arenot recommended for use in swine enclosures.
Metallic coatings are applied to steel sheet by the hot-dip process and are offered in a range of coating weights.The most common coatings specified for exteriorapplications are G90 (galvanized) or AZ50(Galvalume™). For interior applications a lighter coatingmay be appropriate depending on the environmentalconditions. The CSSBI publishes information onrecommended coatings that can be used as a selectionguide. A list of current publications can be obtained fromthe web site at www.cssbi.ca .
Zinc and aluminum-zinc alloy coated sheet steel is apopular construction material by itself. For maximumcorrosion protection, however, a paint coating should beadded to provide both colour an extra barrier toatmospheric corrosion. The organic top coat (paint)inhibits water and oxygen from reaching the underlyingmetallic coated sheet steel, thus effectively minimizingthe corrosion process.
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Prefinished Coatings: "Prefinished" means the sheet steelhas been painted before it is roll formed into thecladding profile. Prefinishing is done in a factory appliedcoil-coating process where paint is applied in a precise,multi-step process. The resulting baked-on paint coatingmeets very severe corrosion protection requirements andaesthetic demands.
Prefinished sheet steel is normally supplied with a fullpaint coat on the top-side (pre-treatment, primer and topcoat) and a pre-treatment plus wash coat on the reverseside. This wash coat, which protects the top side duringrecoiling, is compatible with the top coat but is thinner.A colour-controlled wash coat is recommended forsingle skin applications where the inside surface of thesheet will be visible. The sheet can also be producedwith a full paint coat on both sides. It is important to notethat although different colours can be ordered on eitherside, the paint system must be the same type.
Since the mid-1960’s, prefinished sheet steel claddinghas demonstrated exceptional durability right acrossCanada, thanks to a highly efficient combination ofcoatings. There are different prefinished sheet steelsystems available for exterior use. Consult the sheet steelfabricator member for details on paint systems andcolours.
Selecting a Lightgauge Steel Cladding Profile
There are many lightgauge steel cladding profilesavailable, not all of which are suitable for everyapplication. The selection of the proper profile and sheetthickness will depend upon the strength needed tosupport the loads as well as the profile and colour tosatisfy the aesthetics. Some profiles are designedprimarily for roof applications while others are intended
more for walls. The product literature from the claddingmanufacturer, available through the distributor, willprovide relevant information.
There are a number of general types of profiles definedby the size and spacing of the ribs. Profiles with a low rib(less than 3/4" high) are generally not as strong as thesame thickness of a high-ribbed product. A high-ribbedprofile (ribs higher than 3/4") is more suited to lowerslope roofs where the high rib will make a stronger roofto resist higher snow loads, and allow more standingwater. Talk to your lightgauge steel cladding distributor(e.g. building material supplier or lumber yard); they willbe able to help you select the profile, material, andaccessories to suit your needs.
It is recommended that the cladding selected bemanufactured by a company who is a member of theCANADIAN SHEET STEEL BUILDING INSTITUTE. Thiswill provide assurance to the purchaser that the productis manufactured to industry standards of quality andperformance for lightgauge steel cladding.
Visual Design
The architectural andaesthetic considerationsthat affect the buildingare classified as the“visual design”. Thevisual design is mainlyconcerned with theexterior claddingelements and there are anumber of issues ofsignificance.
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The shape of the profile will affect the look of thebuilding. There are a wide variety of profiles availablefrom the different manufacturers. The profiles can becombined to create different textures over the building.Accent strips and flashings can also add to the visualappeal, especially if co-ordinating colour combinationsare used effectively.
Orientation of the profile also influences the look of thebuilding. Cladding products can be installedhorizontally, vertically or at an angle. There are limits,however, to the horizontal applications without somespecial attention. Some products may be susceptible tooil canning or will trap water in the flutes if placedhorizontally. Consult the cladding fabricator forguidance.
Colour selection is one of the most significant decisionsin the visual design process. The choice of primary andaccenting colours used for the cladding, trims andaccessories will determine the look ofthe building. Contact the claddingfabricator for a colour chart that gives arange of available colours.
Accessories such as flashings, accenttrims, doors and windows affect theoverall look of the building. Theseitems can be highlighted to enhancethe visual appeal of the building or theycan be subdued.
Interfacing with other materials iseasily done with lightgauge steelcladding products. Brick, masonry,wood and other materials can beintegrated into the overall buildingenvelope to develop simple or strikingarchitectural features.
Strength Design
The design of the lightgauge steel claddingcomponents is engineered by thefabricator. Span tables, available for allroofing and siding profiles, are used toselect the proper profile/thickness for theanticipated loads.
The spacing of the supporting purlins orrafters, combined with the anticipatedsnow and wind loads, will determine theprofile type and steel thickness. For thespecific building location it is important tocompare the anticipated loads with the
span table for the particular manufacturer's profile beingconsidered. The cladding sheet also needs to bedesigned to resist wind uplift, which may affect themaximum purlin spacing. The snow and wind loads ona roof will change with the roof pitch and the addition ofvalleys or dormers. These loads are available from theappropriate building code or local building official.Cladding profiles are also available in different strengthsof steel that will have different span tables.
Sheet lengths are manufactured to order for the projectand one of the advantages of sheet steel is the longlengths available. It is desirable where practical to use asingle sheet from top to bottom, however, considerationmust be given to profile and thickness to accommodatematerial handling, transportation and erection. Thelonger lengths may have consequences on the economyof the project where exceptional handling is required toproduce a quality installation. For maximum sheetlengths, consult the cladding fabricator.
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Accessories
Members of the CANADIAN SHEET STEEL BUILDINGINSTITUTE who manufacture lightgauge steel claddingalso offer a complete line of accessories to ensure aweathertight building and enhanced appearance.Products that are classified as accessories include: foamclosure strips, trims, flashings, fasteners, roofingpenetrations and curbs.
Quantity Estimating
(a) Estimating Roof Sheets:When the roofing sheet is one piece from the eave toridge, use the following formula to determine thenumber of sheets needed to cover one area of roof.Depending on the shape of the roof, this calculationmust be done for each area with totals added together todetermine the overall quantity.
N = R x 12c
where: N = Number of sheets per roof areaR = Length of ridge (ft)c = sheet coverage width (in)
(b) Estimating Roof Sheet Lengths:The slope of the roof will determine the length of theroof sheets from eave to ridge. Figure 1 can helpcalculate this sheet length using the horizontal lengthfrom eave to ridge along with the roof slope. If more thanone sheet is needed to cover the length, allow an extra 6in. for the end lap.
(c) Estimating Wall Sheets:The same formula used in determining the number of roofsheets is also used for wall areas. Small openings, mandoors and windows should be included in the calculationof coverage area. In some cases where there are a largenumber of windows or other large openings (e.g. vents,fans or louvres) the number of sheets should be countedone by one to minimize the waste of material. Largesliding doors should be excluded from area calculationsunless they are to be covered with the same material.
(d) Estimating Fasteners:Use the following chart to estimate the number offasteners (per 100 square feet) needed for theproject based on the support and fastenerspacing.
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FIGURE 1 Determining sheet lengths for various roof pitches
SupportSpacing Fastener Spacing
6" o.c. 9" o.c. 12" o.c.
18" 145 100 75
24" 110 75 55
30" 90 60 45
36" 80 55 40
42" 70 45 35
48" 60 40 30
54" 55 40 30
60" 50 35 25
Storage of Lightgauge Steel Cladding
If lightgauge steel cladding must be stored for anextended period of time, the most desirable place isunder roof in a cool, dry, well-ventilated area. Whenstoring indoors, the cladding bundles should beuncovered to ensure air circulation.
When outdoor storage is unavoidable, the following isrecommended:(a) block bundles off ground for effective drainage and
ventilation;(b) block under long bundles to prevent sagging;(c) elevate one end of bundles for drainage;(d) use good quality covers (other than plastic) loosely
shrouded over cladding bundles and anchored toprevent wind blow-off;
(e) store away from chemically aggressive substances(salt, cement, fertilizer), material that couldcontaminate the cladding surface (diesel oil, paint,grease), and site traffic.
Fasteners
Fasteners are a very important part of any building andseveral Canadian companies supply good qualityproducts. Screws are recommended for their betterholding power and sealing. Screws should be installed tofirmly hold the cladding to the structure, but must not beoverdriven since this will cause the washers to squeezeout or dent the cladding. Adjustable torque screw gunsare the best method of ensuring that the screw fastenersare consistently installed to the proper torque.
The number and placement of fasteners will varydepending on the structure being covered. Generally, itis recommended to stitch fasten every 24" along theseam between panels and every 12" to 18" across thepanel width where the panel overlaps asupport. This requirement may vary,however, since different profiles requiredifferent numbers of fasteners. Consultthe cladding manufacturer's specificproduct literature.
Venting
Light Commercial BuildingsMany light commercial buildings areinsulated for human comfort and need toincorporate an effective air/vapourretarder to control the flow of air andmoisture. It is recommended that a
minimum 15 pound felt or slip sheet be includedbetween the steel roofing and the roof sheathing.Alternatively, an air space can be provided under thecladding sheet. For more discussion on recommendeddetailing of insulated sheet steel wall and roofassemblies, consult the lightgauge steel claddingmanufacturer.
Agricultural BuildingsVentilation is a positive step toward adding life to abuilding and providing a healthier environment forlivestock. By reducing summer heat and preventingcondensation in winter, buildings will both performbetter and last years longer.
Every animal confinement building contains significantquantities of moisture vapour created by variousactivities and by the normal respiration of livestock.Some of this vapour can condense on the cladding orstructure and lead to premature corrosion. Unventilatedattic spaces can reach temperatures of 50˚C or more onhot summer days. This heat passes on to the livestockbelow creating potential health problems. Positiveventilation will reduce this condition.
A general rule of thumb is to provide at least 1 sq. ft. ofunrestricted inlet area at the eaves for every 600 sq. ft. ofceiling area with an equivalent unrestricted area of peak
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exhaust. Figure 2 illustrates how aperforated soffit and a ridge ventilator areused to achieve proper ventilation. Theadvantages of a forced air ventilation systemshould be discussed with a qualifiedengineer. Consult the Canadian FarmBuilding Handbook or the ConstructionGuide for Farm Buildings for additionaldesign guidance or your ventilation andsoffit manufacturer for their air flow chartsfor your particular size of building.
Trims and Flashings
The types of trims and flashings normallyused vary among regions in Canada andamong manufacturers: however, there arecertain standard flashings that can be usedto give your building the desired finishedappearance.
Figure 3 shows a number of flashings and their use on abuilding. There is a basic difference in styles betweenflashing types. While some are installed before the steelcladding, others are installed after the cladding: both,however, are effective in providing a weathertightbuilding. Consult your local cladding or trim supplier fortheir list of available stock flashings.
Tools and Equipment
The following selection of tools is generally required toinstall lightgauge steel cladding.* Electric screw gun with adjustable torque * Hammer* Electric drill for pre-drilling fastener holes in sheets* Reciprocating saw, nibblers or shears * Tape measure* Leather gloves* Aviation snips* Chalk line (Make sure the chalk used can easily be
removed from the painted sheet)* Proper safety equipment
Remember to always use leather faced gloves whenhandling metal cladding and trims. Also, if using a sawto cut prepainted sheets, make sure that the paintedsurface faces downward and keep away from othersheets because the hot filings will damage the paintfinish.
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especially animal confinement structures. Check with an engineer.NOTE: This may not be sufficient ventilation for all buildings,
EAVE
RIDGE
Rafter
Siding
Air
Perforated
Roof Sheet
Closure Strips
Air
Roof Sheet
Continuous Ridge Ventilator
Soffit
FIGURE 2 Ventilation under roof sheets
Base Flashing
Fascia
Closure Strip
Roofing Panel
Fitted Ridge Cap
Closure Strip
Soffit
Siding Panel
"J" Trim
Caulking
Window andDoor Flashing
FIGURE 3 Typical trim locations
Erection Safety
The members of the Canadian Sheet Steel BuildingInstitute subscribe to the principle of performing erectionwork in the safest possible manner consistent with goodconstruction practice. It is the responsibility of theroofing and siding erector to ascertain and follow theappropriate regulations governing construction safety forthe type of structure and specific location. The followingrecommendations are only intended to supplementgoverning regulations and highlight issues that may bespecific to sheet steel roofing and siding.
Personnel ProtectionThe erector’s employees shall wear such personalprotective clothing, equipment or devices as deemednecessary for the individual’s protection from theparticular hazards associated with the installation oflightgauge steel products. This equipment shouldinclude, but is not limited to, safety hats, safety belts,safety footwear, eye protection and gloves.
Job Site HousekeepingThe erector shall maintain the job site in a safecondition, including all means of access to the workarea. No equipment or material shall be stored so as topresent a hazard. All cuttings, strapping, packingmaterials and other debris pertaining to the trade shall becleaned-up and disposed of as often as necessary toprevent a hazardous condition.
Safety While HoistingThe erector shall ensure that proper material hoistingequipment is utilized and is in good repair. The operatorand supporting personnel must have adequate trainingand review the safe operating procedure appropriate tothe equipment being used. During lifting, moving orhoisting, no one is permitted to stand or pass undersuspended loads.
LaddersWhen used, ladders shall be of a type appropriate for theintended use and kept in good repair. Where metalladders or metal reinforced ladders are used, proper careneeds to be exercised that the ladder does not come inclose proximity to uninsulated, energized electricalequipment or conductors. Ladders must be placed onfirm footing, with the base located between one-quarterand one-third of the length from the base of the wall orstructure. Where ladders are used as the regular meansof access or egress from different levels, the ladder mustbe firmly secured in place.
Tools and EquipmentThe erector shall instruct employees in the proper use ofthe applicable tools and equipment. All power tools arerequired to have reliable ground fault protection.Powder-actuated tools are only to be used by employeesauthorized and specially trained in the proper care anduse of such tools.
Installation
The following is a step-by-step guide for the installationof lightgauge steel roofing and siding in an agriculturalapplication. The same basic procedures will apply in acommercial project. The applicator is responsible forknowledge of local construction practices and buildingcode requirements that may apply.
To begin, identify the side wall sheets, end wall sheets,sliding door sheets, roof sheets and all trim and flashingpieces. Prearrange them in a convenient location nearthe portion of the building being covered. Be certain touse the correct length of sheet in the right areas andsecure or protect sheets from the wind at all times.
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NOTE: If you have any doubts or concerns about theapplication of cladding, trim or fasteners. STOP! Checkwith your supplier. These following steps arerecommendations only: use common sense.
STEP 1: Material ChecklistIt is important to make sure that all of the necessarypieces are on hand before the project is started. Thereare some trim items that are absolutely necessary to beinstalled before the cladding and work cannot continuewithout them. To avoid any delays due to materialshortage, double-check the inventory of items.
STEP 2: Install Roof Trim, Flashing and MembraneThere are many types of flashings and trims available,some of which are purchased and others that can befabricated on-site. The examples used in this guide areonly representative of the products available, and maynot be recommended in certain applications. Consultthe cladding manufacturer for advice as needed. Careshould be used in the on-site fabrication of flashings toensure a good looking and weathertight job.
While a minimum number of flashings are needed toensure a weathertight building, some trims are optional
and can be used to enhanceappearance. The followinginstallation instructions refer toflashings and trims illustrated inFigures 4 and 5. The flashingsshown in Figure 4 are the morecommon types. The flashingsgiving in Figure 5 are either StyleI, installed before the cladding,or Style II, installed after thecladding. Determine which typeyou have purchased and followthe appropriate installationprocedure.
(a) Gable Trim (Style I):To install the Style I gable trimpieces as shown in Figure 5, fitthe pieces in place, fasteningthrough (at 36" spacingmaximum) both top and bottomnailing flanges. If this type of trimis used, it is important to properlyseal (sealer tape is commonlyused) and fasten the claddingsheet along the gable to preventwater from migrating under thesheet and into the building.
(b) Eave Trim (Style I and Style II):Style I and Style II eave trimpieces, shown in Figure 5, areinstalled before the roof sheets.For Style I, install as shown. ForStyle II, determine the wall paneldepth (e.g. 3/4") and fasten thetop nailing flange of eave trim toallow a space for the wall panelsplus a 1/8" clearance. Use at leastthree fasteners per ten-foot lengthof trim.
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Ridge Cap
"J" Trim
Jamb Flashing
Base Flashing
Inside Corner Flashing
Drip Flashing
Gable Divider
Door Head Flashing
FIGURE 4 Standard flashings
(c) Corner and Ridge Boxes:Corner and ridge boxes are optional items and areinstalled after the eave and gable trims are in place.Follow the manufacturer's directions.
(d) Dormer and Valley Flashings:Where required, install the valley flashings as shown inFigure 6. It is important that the valley flashing besupported by sheathing or blocking along its entirelength. Without this support the flashing will not lie flatand it will be impossible to make a weathertight sealbetween the roof sheet and the flashing.
The size and shape of valleyflashings differ from one roof toanother. A low-pitch roof mayrequire a 36" wide valley flashing,whereas a higher-pitch roof mayonly require one 24" wide. Theroofing sheets should be cut at anangle to accommodate the pitchof the valley. A "W" valley is moreeffective in channeling water offthe roof than a "V" type. Careneeds to be taken to close off thecladding ribs to prevent waterbacking up under the sheet.
Flashing where the dormer meetsthe main roof area can be donewith a field-fabricated section.The dormer ridge cap needs to becut and fitted under the main roofsheets.
(e) Membrane:When sheet steel roofing isinstalled over a sheathing materialsuch as plywood, it is commonpractice in some regions to installfelts or a peel and stick membraneover portions of the roof area.Consult the local roofingapplicator or fabricator forrecommendations.
STEP 3: Roof Sheets(a) The first thing is to check theroof squareness. At the cornerwhere an eave and gable meet,measure eight feet along the eavepurlin and mark. Then measuresix feet up the gable edge from theeave and make another mark.
Measure the distance between the two marks. If it isexactly ten feet, you have a square roof at that corner(see Figure 7). Check all roof corners using thisprocedure.
NOTE: The following instructions assume that the roofis square. If the roof is not square there are twocorrection methods that can be used depending uponthe severity. If the deviation is not too significant, it canbe corrected a little sheet by sheet taking advantage ofthe tolerances in the sheet side laps. For very unsquareroofs, the sheet along the gable can be trimmed along itslength to match. A gable flashing is used to reduce thevisual impact of the trimmed sheet.
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Gable Trim - Style I
Eave Trim - Style I
Outside Corner Flashing - Style I Outside Corner Flashing - Style II
Eave Trim - Style II
Gable Trim - Style II
FIGURE 5 Style I and Style II Flashings
(b) Identify the proper seam lap and the proper screwplacement to fasten the sheets to the building.
NOTE: When walking on a roof, avoid walking on theribs. Step where the purlins are and follow the fastenersup or across.
(c) To get the roof sheets up on the roof, put a board orladder against the fascia board and slope to groundas far away from the building as possible. Using visegrips and a rope, pull sheets up the board and ontothe roof. This method is not suited to long sheets.Extra care needs to be taken on windy days toprevent the sheet from buckling or getting out ofhand. Work safely.
(d) Start at the eave on the end of the building farthestaway from the prevailing winds. Extend the sheet
about 1" over gable edge and1" to 2" over the eave.
(e) Overlap sheet ends by atleast 6". Sheet endoverlaps should only bemade at a purlin forsupport. Lay sheets one byone from eave to ridgebefore commencingsecond row (Figure 8). Donot fasten open side beforestarting next row. Exceptfor large buildings, a singlesheet will span from eaveto ridge without requiringoverlaps.
(f) Check sheet alignmentevery four to five rows bychalking a line square tothe eave.
(g) Leave the required space atthe ridge to accommodatethe ridge ventilators asillustrated in Figures 9 and10.
STEP 4: Install Ridge VentilatorsThere are a number of ridgevent types, two are shown inFigures 9 and 10. Theinstallation procedures areessentially the same for bothas follows:
(a) Install the roof sheets leaving the required opening forthe ridge vents as specified by the manufacturer. Forindividual vents, notch sheets at the ridge accordingly.For continuous vents, the roof sheets should stop shortof the ridge to leave the required gap.
(b) Install the vent over the ridge opening, following themanufacturer's instructions, and use foam closurestrips suited to the cladding profile to ensure that thebuilding is sufficiently weathertight. Make sure thefoam closure strip does not block drainage holes inthe ridge vent. When fastening the ridge vent, drivethe screws through the foam closure to keep it inplace.
(c) Vents should be fastened through the ribs of the roofsheets and a generous bead of caulking must be
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On-Site Flashing
Valley Flashing
FIGURE 6 Valley Flashing
8'
10'6'
Square Roof Un-Square RoofGable
Ridge
Eave
FIGURE 7 Check roof squareness
applied between the ridge cover and the vent endflanges.
(d) For a ridge longer than the length of a single vent(normally 10 feet) butt two vents together with theconnector flange underneath at the joint. Both ventand end panels fit between the two tabs on theconnector flange. End panels are used when ventsare installed individually.
STEP 5: Install Ridge Cap(a) Chalk location of ridge cap on both sides of roof.
(b) Install closure strips along chalk line with adhesive.
(c) Place ridge cap on top and fasten through top ofcladding rib and through closure strip.
(d) Caulk overlapping portion and place next ridge capon top, repeating the above steps.
(e) Caulk also around ventilators and other areas wherenecessary.
STEP 6: Install Gable Trim (Style II)Style II gable trim is installed after the roof sheets havebeen installed. If you are using this type of trim, it shouldbe installed at this time as shown in Figure 5.
STEP 7: Install Base Flashing(a) Measure side wall sheeting length and add 1" to
determine location of base flashing.
(b) Measure nailing flange of base flashing.
(c) Subtract (b) from (a).
(d) Using the measurement found in (c), chalk a linearound the building.
(e) Install base flashing, matching the top of the nailingflange to the chalk line. Using fasteners every 24",fasten trim.
(f) Figure 4 shows the application of a base flashing.
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5
3
1
4
2
Vent Connector Flange(For Running VentsContinuously - ReplacesVent End Flange)
Drainage Holes
Vent End Flange
Ridge Cap
Tab
Vent Roof Flange
Foam Closure Strip
Roof Cladding
Vent End Panel
FIGURE 8 Location of Roof sheets
FIGURE 9 Low profile ridge vent
STEP 8: Other Wall Trims and FlashingsDepending upon the type of building, there are anumber of other flashings and trims needed to close offaround the various wall penetrations such as doors andwindows. The following describes some of the morecommon types as shown in Figures 4 and 5. Here again,some wall flashings and trims are installed before thewall cladding while others are installed after thecladding. Make sure you know which type you areusing.
(a) Inside Corner: Figure 4 shows the application of aninside corner trim installed before the wall siding.
(b) Outside Corner: Figure 5 shows the application ofan outside corner. Note that there are two styles, oneinstalled before the siding (Style I), the otherinstalled after the siding (Style II).
(c) Gable Divider: Figure 4 shows the application of agable divider which is installed after the end wallsiding, but before the gable siding. A gable divider isnot needed if the end wall sheets are cut to fit theslope of the roof.
(d) Jamb Flashing: Jamb flashing as shown in Figure 4 isused around door openings and installed before thewall siding.
(e) J Trim and Drip Flashing: Figure 4 shows theapplication of J trim and drip flashing in a window
detail. These flashings can be used in different typesof applications.
(f) Door Head Flashing: Figure 4 shows a flashing thatcan be used at a door head.
STEP 9: Wall SheetingInstall the side wall and end wall sheeting, beginning onthe side opposite primary view, usually the rear wall ofthe building. This will produce the best appearancesince the sheeting laps will be out of immediate view.
(a) Identify the proper seam lap and the proper screwplacement to fasten the sheets to the building.
(b) Begin placing sheeting on the side wall at the corner.It is very important to use a level to plumb the wallsheets before fastening.
(c) Check seam lap to ensure a snug fit.
(d) Run the first two fasteners through the girt to holdthe sheet in place.
(e) Finish fastening the wall sheets using the properscrew placement, ensuring that the sheets are squareand laid evenly.
(f) Continue to fasten the wall sheets around thebuilding, finishing with the gable ends.
Lightgauge Steel Roofing and Siding
how to series...14
Vent End Flange
Vent End Panel
Roof Cladding
Foam Closure Strip
Vent Roof Flange
Ridge Cap
Screen
FIGURE 10 Standard ridge vent
STEP 10: Caulking and Clean-up(a) Caulk around windows and doors for that
professional look.(b) After the cladding sheets are installed, take a soft
bristle broom and sweep the sheets to remove anysteel shavings or other dirt. Steel particles left on thecladding will rust very quickly, often staining thepaint finish, giving the impression that the roof sheethas rusted. Dirt left on the sheets will hold moistureand accelerate the deterioration of the paint system.
General RecommendationsThere are a number of recommendations that do notdeal specifically with the installation of lightgauge steelcladding, but which help to ensure a successful project.
(1) Inspect the shipment of cladding panels upondelivery.
(2) Moisture can cause wet storage staining whichappears as an unsightly white stain, leading to redrust. A nominal amount of staining on material is notdetrimental, however, to the functioning of theproduct.
(3) Abrasive cutting toolsare not recommendedfor cutting prefinishedsteel cladding. Anycutting method thatgenerates excessivesparks or heat candamage the paintedsurface.
(4) Walking on prefinishedmaterial should beavoided. However, when
you must do so, wear clean rubber-soled shoes toavoid scratching the surface and slipping or fallingoff the roof.
(5) Fasteners, cuttings, etc. must be removed from theroof, gutters, etc. as installation progresses.
(6) Materials that can trap moisture such as dirt, wood,rags, etc. should not be allowed to accumulate onthe cladding surface.
(7) Any burrs should be removed with a file or shears.Filings should be removed immediately. Overnightdew is often sufficient to cause these particles to rust,and sometimes stain light-coloured material.
(8) To ensure an even application of all sheets, do notsecure all fasteners on a panel until the sheet hasbeen laid and squared.
We wish you success in installing lightgauge steelcladding on your project. We hope that this guide willhelp you plan and execute a successful job. Feel free toconsult your local installer or cladding manufacturer forextra help.
![CSSBI-Steel Roof Deck Floor Deck[1]](https://static.documents.pub/doc/80x56/552e8098550346231a8b49af/cssbi-steel-roof-deck-floor-deck1.jpg)
