Installation & Handling
Gshan Sheets are pierce-fixed to steel or timber supports. This means that fastener screws pass through the sheeting. You can place screws for Gshan Sheets through the crests or in the valleys. To maximize water tightness, always place roof screws through the crests. For walling, you may use either crest- or valley fixing. Always drive the screws perpendicular to the sheeting, and in the centre of the corrugation or rib. Don't place fasteners less than 25 mm from the ends of sheets. All the fasteners shall confirm to CLASS 3 for external application.
Side-Laps
It is generally considered good practice to use fasteners along side-laps however, when cladding is supported, side-lap fasteners are not usually needed for strength.
End lapping
Gshan sheets are available in long lengths and therefore end laps are not always necessary. If your design required end-laps, seek advice from your nearest Gshan office.
Ends of sheets
It is usual to allow roof sheets to overlap into gutters by about 50 mm. If the roof pitch is less than 25 degree or extreme weather is expected, the valleys of sheets should be turned down at lower ends, and turned-up at upper ends by about 80 degree. When Gshan Sheets are laid on slopes of 5 degrees or less, cut back the corner of the under-sheet, at the down- hill end of the sheet, to block capillary action.
Laying procedure
Begin laying sheets from the end of the building for maximum weather-tightness. Before lifting sheets on to the roof, check that they are the correct way up and the overlapping side is towards the edge of the roof from which installation will start. It is much easier and safer to turn sheets on the ground than up on the roof. Place bundles of sheets over or near firm supports, not at mid span of roof members.
Maintenance
Optimum product life will be achieved if all external surfaces are washed regularly. Areas not cleaned by natural rainfall (such as the tops of walls sheltered by eaves) should be washed down every six months.
Storage and handling
Maximum support spacing Keep the product dry and clear of the ground. If stacked or bundled product becomes wet, separate it, wipe it with a clean cloth and stack it to dry thoroughly. Handle materials carefully to avoid damage: don't drag materials over rough surfaces or each other; carry tools, don't drag them; protect from swarf.
Cutting
For cutting thin metal on site, we recommend a circular saw with a metal-cutting blade because it produces fewer damaging hot metal particles and leaves less resultant burr than a carborundum disc. Cut materials over the ground and not over other materials. Sweep all metallic swarf and other debris from roof areas and gutters at the end of each day and at the completion of the installation. Failure to do so can lead to surface staining when the metal particles rust.
Walking on roofs
Generally, keep your weight evenly distributed over the soles of both feet to avoid concentrating your weight on either heels or toes. Always wear smooth soft-soled shoes; avoid ribbed soles that pick up and hold small stones, swarf and other objects.
Metal & timber compatibility
Lead, copper, bare steel and green or some chemically treated products of timber are not compatible with this product; thus don't allow any contact of the product with those materials, nor discharge of rainwater from them onto this steel product. If there are doubts about the compatibility of products being used, please contact Gshan office for advice & recommendations.
Maximum support Spacing
The maximum recommended support spacings are based on testing in accordance with AS1562.1-1992, AS4040.1-1992 and AS4040.2-1992. Roof spans consider both resistance to wind pressure and light roof traffic (traffic arising from incidental maintenance). Wall Spans considers resistance to wind pressure only. The pressure considered (in accordance with IS 875.3) is based on buildings up to 10m high, Zone 3 (Basic wind speed Vb = 47m/s), Class A, Terrain category 3, K1 = 1.0, K2 = 0.91, K3 = 1.0, with the following assumptions made;