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.
Roof cladding design does not usually have to be altered for snow load, but it may be necessary to increase the strength of the structure to allow for induced snow loads.
The maximum snow load in New Zealand (under NZS 3604) is a UDL of 2 kPa. Collapse under snow load would be a strength failure, since 2 kPa is less than the upwards load in a Very High Wind Zone. However, as it is a downwards load, restraint is linear by the purlins, rather than point restraint by the fasteners, so greater capacity is achieved.
Any profile-gauge combination that will resist a wind load of Very High or Extra High Wind Zone with fasteners at each crest, will adequately resist a 2 kPa snow load.
|Snow Loading Allowance is not required for Zone 0|
|Zone||Up to:||1.0 kPa||1.5 kPa||2.0kPa|