The NZ Metal Roof and Wall Cladding Code of Practice is a comprehensive design & installation guide, and a recognised related document for Acceptable Solution E2/AS1 of the NZ Building Code.
As PVC and polycarbonate expand almost six times more than steel, they should only be used in lengths not exceeding 3 m. Translucent plastic sheets, however, do not normally reach the same temperatures as adjoining metal sheets.
|mm per 50° C per 1 m length|
PVC and polycarbonate sheet in lengths up to 3 m require 6 mm oversize holes to all fixings. The fixings should always be fitted in the centre of the holes, which can be achieved by pilot drilling. It is recommended that a stepped drill bit be used to ensure the correct size hole.
Special screws which drill their own clearance hole are suitable for polycarbonate and GRP sheeting.