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Roofing Cladding Sheeting supplies

The following installation notes are as per Cladco-LJT recommendations.

SAFETY
When Installing roofing and cladding sheeting supplies the user should exercise special care when handling long length sheeting, particularly in windy conditions. Should work be interrupted for any reason, all loose sheeting and incomplete sections must be adequately secured against possible movement by wind and gravity. Care should be taken of sharp edges when handling sheets. Suitable gloves should always be worn.

Installing Roofing and Cladding Sheeting supplies
 WALKING ON ROOF SHEETING
Deck/crawling boards should be used when walking on profiled sheeting and walk on at least two ribs at a time. When walking across the width of roof sheeting, walk over or close to the roofing supports. Generally keep weight evenly distributed over the soles of the feet.
Clean soft soled shoes should be worn. Care should be taken with new sheets as they may be slippery.
Installing Roofing and Cladding Sheeting supplies

Installing Roofing and Cladding Sheeting supplies

HANDLING AND STORAGE
Roof sheeting is delivered in bundles and should always be stored in a dry and safe area. Bundles should be stored clear of the ground and protected by waterproof covers. If bundles become wet, the sheets should be separated, wiped with a clean cloth and stacked to allow air circulation and complete drying. Do not store heavy materials on top of sheets.
Every precaution shall be taken to prevent damage to roof sheets during all stages of construction. Deck boards should be used when necessary to protect the sheeting from damage. Sheeting which has become deformed or damaged in any way should be replaced.

INSPECTION PRIOR TO INSTALLATION OR ERECTION
Before commencing installation, the user shall verify that the following items have been checked and accepted:

a. The entire structure or the portion thereof to be sheeted has been correctly aligned and levelled.

b. Purlins and sheeting rails are at the correct spacing and are within the specified tolerances.

c. The corners of the roof are square and the wall framework is perpendicular or as specified.

d. No protrusions such as bolt heads, splice plates, cleats, etc. appear on the face of the framework.

e. All members to which roofing and cladding are to be fixed in aesthetically sensitive areas are true and square.

f. Paint and any other materials that may be incompatible with the sheeting, have been painted over or so dealt with so that direct contact with the sheeting is avoided.

g. The contact faces between the purlins and the cladding are in the same plane. Should the alignment be inadequate, the user shall request instructions from the engineer before proceeding with the fixing of the cladding.

PROTRUSION THROUGH SHEETED SURFACES
Protrusions such as pipes, ducts and the like, shall be adequately flashed where they pass through the sheeting surface. Where ribs have to be cut away to permit penetration, additional framing is to be installed as required to support the sheeting.

Depending on the position of the penetration through the roof, special attention shall be given to back flashing the sheeting to the ridge or point of water entry. In all cases, all cutting and flashings shall be so arranged that adequate provision is made for the drainage of all troughs and corrugation.
CUTTING SHEETS ON SITE
Should cutting of the sheet onsite be necessary the use of an angle grinder with a small tooth blade or disc is recommended. Care should be taken to achieve a cut with minimal damage to the sheet. Reciprocating nibblers are also widely used in the roofing trade and produce an excellent cut. Small sharp scrap pieces should be carefully collected to avoid personal injury or product damage.

When cutting roof sheeting take care to protect the sheeting from debris. Whenever possible, cutting should be done on the ground and not over other coated material. Sheets should be placed face down on padded supports. Cutting should not be carried out on top of other painted surfaces.
ROOF PITCH
The minimum roof pitch for profiled roof sheets is 5º, however roof pitches of 3º are allowed for short lengths. For corrugated sheets we recommend the roof pitch should not be less than 10º.

LAYING PROCEDURE
The spacing of the purlins will depend on the thickness of the sheets used. As a guide, maximum spacing of purlins for 0.5mm thickness sheets is 1200mm. The purlins should be a minimum of 50mm in width in order to be easily nailed or screwed.
The laying of the sheets should commence from the eave and away from the prevailing wind. The side laps will then be away from the wind preventing water from being forced into the lap.

It is very important that the first sheet be laid at right angles to the eave and the ridge for by so doing, all the rest will also be perpendicular with the ridge. The first row of sheets is laid with a 50mm overhang beyond the facer board.

FIXING PROCEDURE
Apart from just attaching the sheets to the frame work and supporting their self weight, the fixings have to withstand considerable wind pressures and be weather-proof and durable. In profiled metal roofing and cladding applications, self drilling screw fixings shall be fitted through the lower trough/pan section of the profile, or if fixing corrugated sheets or using nail fixings, through the crest of the profile. Due to the larger expansion and contraction rates of fibreglass GRP and plastic sheeting, oversized fixing holes must be pre drilled in these sheets, otherwise install screws into fibreglass in the same manner as metal. Under average conditions, the fixings should be placed at every second corrugation or trough on the purlin. A stretched string along the purlin makes it easier to fix the sheets. Extra fixings are needed along the verge (gable end overhang). Roofs in exposed positions require closer fixing.
It is important not to over tighten the screw putting undue pressure onto the sheet.
SIDE LAP FASTENERS
It is generally considered good building practice to include side lap fasteners at the overlapping joint between sheeting. In these cases the fasteners will bond the adjacent sheeting together. Stitching screws are recommended in these instances to maintain a weather resistant joint, however when roof and wall sheeting is installed within the spanning guidelines, side lap fasteners are not always required.

In general, roof sheets are laid with spacings left available for the skylights. Each individual fibreglass sheet is manufactured to overlap and be supported by adjacent roof or wall cladding.

END LAPS
At all end laps a minimum of 300mm overlap shall be provided and such lap shall be supported with a purlin. All sheets, when fastened, shall have full bearing on purlins and their ends shall extend not less than 150mm beyond the point of fastening.

At all end laps between sheeting, strip of flexible lapping tape sealant shall be placed across the full width of the lap approximately 25mm from the end sheeting.

Gaps in the pans/trough of dissimilar materials (metal sheet and GRP rooflights) can occur. Lapping tape fills up these spaces much more effectively than silicone. The end lap fixing methods are the same for metal onto fibreglass. Fibreglass onto fibreglass, or fibreglass onto metal.

installing roofing

SEALING AT FLASHINGS ON ROOFS
Roof sheeting is not easily reshaped after manufacture and will require special weather seals to be provided at all flashing and capping points. Typically a foam filler/closure strip matching the profile of the sheeting should be provided to seal the corrugations or pans of the profile under each flashing and at the eaves.

The foam closure should be bonded to the pans or valleys of the plastic sheeting with a flexible waterproof sealant and should be continuous over the entire width of the sheeting.

Ridging and side flashings are normally available in pieces of 3m length. They should be fitted with a 150mm overlap. Other accessories such as eaves-filler, ridge-filler pieces and lapping tape are available

CLEANING OF ROOF, ETC.
All debris, swarf, etc arising from the fixing of the cladding shall be removed from the sheeting as the fixing progresses. In addition, off-cuts of insulation, surplus fasteners and sealants, mandrels from pop rivets, off-cuts of flashings and sheeting, surplus flashing, food packaging, cartons, bottles, cans, etc shall not be left on the roof or in the gutters.

Care shall be taken to ensure that no such material enters, blocks or partially impedes the flow of water into the outlets, down pipes, etc.