Posted: 30 May 2019
Clauses E3.3.3 and E3.3.5 state that surfaces must not only prevent water seeping through them but also be 'easily cleaned'. The Building Code does not define 'easily cleaned'.
A designer submitted a building consent that included the use of carpet glued over a concrete slab for a laundry in an attached garage. The carpet was described as 'non-absorbent', but was not impervious.
The building consent authority (BCA) and designer disagreed over whether the proposed carpet could be 'easily cleaned'. The designer believed it could, using the carpet supplier's cleaning procedures: vacuuming, spot cleaning with warm water and detergent for soiling, and the use of a wet and dry vacuum to remove moisture. The BCA believed the carpet was not easily cleaned and would allow mould to grow.
The determination considered the functional requirement of Clause E3.2(a) to help define 'easily cleaned'. It requires buildings to be constructed to avoid the likelihood of mould growing or build-up of contaminants on surfaces and other building elements. Therefore, the determination considered 'easily cleaned' meant that any contamination could be removed with little exertion and without specialist equipment.
For guidance, the determination referenced the finishes and linings listed in E3/AS1 as impervious and easily cleaned. These surfaces shared common features, which included being solid, dense, flush, smooth, uniform, and were waterproof. Little exertion or specialist equipment would be needed to clean these surfaces.
In this case, the proposed carpet was soft, textured and uneven, which increased the chance of contaminants becoming trapped. The increased effort to clean textured surfaces meant it was likely that not all contaminants would be removed. This would result in the build-up of contaminants over time in the carpet.
The determination decided the carpet would hold contaminants and remain wet for longer periods of time than those surfaces listed in E3/AS1.
It was found that the carpet in the laundry space of an attached garage did not comply with the 'easily cleaned' performance requirement of clauses E3.3.3 and E3.3.5.
You can read previous determinations in the determinations register.