Cavity wall insulation solutions are coming under greater scrutiny as they gain popularity with the transition to 6-Star energy efficiency requirements.
Leading insulation innovator, Kingspan Insulation, urges consumers, regulators and the building industry itself to be mindful of the insulation products being installed in cavity walls.
According to Kingspan Insulation Technical Manager, Mr. Keith Anderson, some products currently being used may not be compliant with the Building Code of Australia (BCA).
“Products that fill the cavity in a double brick wall, such as “full-fill” insulation systems, potentially contravene the building code deemed-to-satisfy provisions for weatherproofing which requires the wall to comply with AS 3700 Section 4.7Prevention of water penetration,” he says.
“The reason for this reference is to prevent moisture ingress migrating across the cavity to the inner wall.”
Clause 4.7.1 of this standard states that ‘In cavity walls and masonry veneer walls, cavities with a minimum width of 40 mm, which are properly detailed and constructed, shall be regarded as being resistant to the passage of moisture from the exposed face through to the inner, unexposed face of the wall’.
This poses a potential problem for insulation systems that fill the cavity, according to Mr. Anderson.“Clearly, a ‘full fill’ insulation system, where the insulation fills the full width of the cavity and is generally ‘blown’ into the cavity, potentially provides a possible channel for moisture to bridge across the cavity, particularly if any variability of density or inadequacy of coverage is present”.
Mr. Anderson says excessive moisture can have serious health-related side effects for a building.
“Moisture problems and undue dampness can lead to mould growth, which can ultimately impact the indoor environment quality of a home and can even cause structural damage.”