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.
Edging materials must be compatible with the flashing and cladding material.
Edging material must have durability no less than the flashing material.
Edging must be able to be dressed to within 3 mm of the pan of all profiles, and 5 mm to the corner of trapezoidal profiles
Edging Material must be sufficiently rigid to maintain its form and function in normal wind conditions.
Metallic soft edge may be backed by an inert layer of other material to improve stiffness and shape retention. Perforated metallic soft edging without a back is also acceptable.