Snow Loads

Roof cladding design does not usually have to be altered for snow load, maximum snow load in New Zealand (under NZS 3604) is a UDL of 2 kPa.This 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. It may, however, be neccessary to increase the strength of the structure to allow for induced snow loads.

NZS 3604 divides New Zealand into six zones where the maximum snow load is 2 kPa; areas above specific altitudes in these areas require specific design.

Projections such as gutters, flashings and chimneys need additional fixings and detailing to resist loads from sliding snow. It is normal to fit snow straps to residential gutters in snow prone areas.

Snow Loadings Map

Snowload Map