What is a Free Drainage Cavity System?
In 2004, councils passed new regulations for plaster system houses requiring that a cavity be formed between the plaster cladding and the exterior timber framing. This is a cavity of approximately 20mm or greater which is formed between the exterior cladding of a building and the structural framing, using tanalised timber battens or similar.
This allows any water that does enter in through the exterior cladding to escape through the cavity before reaching the main timber structure. This cavity also allows for greater air circulation which assists in preserving the integrity of timber framed houses.
Many plaster system houses built prior to 2004 have not been constructed using a free drainage cavity system.