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.
The purpose of a flashing is to divert water away from any point of entry and to make a building weatherproof.
Flashings are not only required to weather the many junctions on a roof or wall structure but are often a highly visible part of the roof and wall cladding design. Therefore, they perform an important role in the aesthetic appearance of the building.
It takes longer to make and install flashings than fixing roof or wall cladding, so designers should be aware of the cost effects of design complexity.