The introduction of cavities was designed to protect the structural component of buildings. As per the building code E2/AS1, on one side of the cavity is the structural framing with a 50 year durability requirement. On the other side of the cavity is the cladding with a durability requirement of 15 years. So where does the 35 year gap in durability protection start and finish?
According to cladding appraisals, the cavity batten is included with the cladding specification. So the line of liability must be where the cavity batten meets the building wrap.
So where in the makeup of the cavity is the moisture barrier to protect the framing? Normally, the first thing builders do when they put down framing on a concrete slab is install a moisture barrier. So why is the same level of protection not also given where there is porous moisture-absorbing cladding? If a timber batten is utilised there is no moisture barrier and the timber can absorb and transfer moisture across the cavity.
Cavibat Cavity Battens are manufactured from polypropylene. Polypropylene is a moisture barrier and the life expectancy of polypropylene is greater than 50 years. The Cavibat system utilised with most claddings can provide superior cavity durability protection for the life of buildings throughout New Zealand.