Safety and Fitting of cladding

Guidelines for use of cladding

Always use the recommended steel grade to suit your environment and any special corrosive influences,
Store material clear of the ground and protect from rain and moisture prior to installation,
Always use fasteners with durability equal to the material being used and which have carbon-black-free washers,
Avoid materials and liquids which can cause corrosion, such as lead and copper, green or CCA (Copper-Chrome-Arsenic) treated timber, uncoated steel supports, fertilisers, pesticides and abrasive cleaners,
Follow manufacturers recommendations for roof pitch, fastener spacings and type, support spacings and other laying procedures when installing products,
Avoid the use of black carbon ('lead') pencils for marking sheets,
Use metal cutting discs or shears to cut sheets rather than angle grinder discs.
Use only neutral cure silicone rubber sealants,
Debris from cutting, piercing & screwing should be removed at the end of each day, and not left on the roof or in the gutters,
Avoid immersion in concrete, soil or water, or build up of debris against the product,
Avoid contact with brick cleaning acid,
Avoid using touch up paint,
Areas not washed by rainwater should be hosed down at least every six months (more frequently in areas with industrial fallout or high salt concentrations).

SAFETY

When installing Shannonclad and “No Drops” roofing and cladding sheeting and 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.
Zinc Processors Limited shall not be responsible for and disclaims all liability for any loss, liability, damage (whether direct, indirect or consequential), personal injury or expense of any nature whatsoever which may be suffered by you or any third party (including your company), as a result of or which may be attributable, directly or indirectly, to your use of our fabrication drawings and measurements. Figures and comments given in this brochure are given for guidance purposes only. While care has been taken to ensure accuracy Zinc Processors Limited and its related companies do not accept liability for errors or omissions. All calculations carried out by Zinc Processors are to aid our production process and in no way constitute a design element. We would strongly recommend that you seek professional advice from a Qualified Engineer or Architect that will ensure that you achieve your desired result. Customers should satisfy themselves of the suitability of the products supplied or manufactured by the Company for the use intended.

WALKING ON ROOF SHEETING
Deck/crawling boards should be used when walking on profiled sheeting. 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.

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 should 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 timbers 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.

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

Depending on the position of the penetration through the roof, special attention should be given to back flashing the sheeting to the ridge or point of water entry. In all cases, all cutting and flashings should 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 should 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 poly carbonite, 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.
It is not recommended that you use polycarbonate clear lights or limelights with “No Drops” anti-condensation cladding.

END LAPS

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

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.

ROOFLIGHTS

in the case of polycarbonate rooflights it is essential that;

The rooflights overlap the metal sheet profile on both sides
Where sealant tapes are required, only those compatible with polycarbonate are used e.g. cross linked butyl .
Holes for primary fasteners are at least 75mm from ends of sheet at top end lap and bottom end lap, and are pre-drilled, minimum 10mm diameter, to provide for thermal movement.
Holes for secondary fasteners are 10mm diameter to allow for thermal movement.
The metal sheet upslope lapping on to the rooflight is fixed through every alternate crown on the end lap.
Primary and secondary fasteners have washers of minimum diameter of 19mm.
Washers have bonded-on EPDM or other material compatible with polycarbonate.
Screw fasteners to timber purlins have the appropriate thread form and penetrate the timber no less than 45mm. Drive nails should have 19mm washers with bonded-on EPDM or other material compatible with polycarbonate.
Fasteners, screws or drive nails, should not be over-tightened: at optimum tightness the washer should just turn when gripped between finger and thumb and torque applied.
There are no aggressive environmental conditions or chemicals where the material is used.
Where purlin centres exceed 1500mm or are less than 1000mm guidance is obtained.
Wind and snow load conditions are taken into account when determining purlin centres.
Installation is otherwise as per supplier’s general recommendations.

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, should 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.