The National Construction Code (NCC) requires that all external walls, from traditional masonry construction through to walls with high performance cladding systems, must be weatherproof to prevent dampness and unhealthy conditions for the occupants. The NCC provides a range of Deemed-to-Satisfy Provisions for Class 1 buildings in BCA clause P2.2.2. However, there are no Deemed-to- Satisfy provisions for external walls in Class 2 to 9 buildings and compliance with BCA Clause FP1.4 must be satisfied by a performance solution.