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.
Aluminium is a naturally durable material with proven performance over a long period.
Most metals compatible with Galvanised and Aluminium/Zinc coatings are compatible with aluminium. However, to acquire the required fastener durability, use aluminium or stainless screws rather than painted steel screws.
Aluminium has approximately twice the thermal expansion of steel, therefore, expansion provisions must be executed as for steel of twice the length.
Being soft and frequently requiring oversize holes for expansion, aluminium is typically fastened with fasteners equipped with load spreading washers, as is reflected in published span tables. Installers must adhere to published fastening systems to meet design load/span expectations.