The Victorian Building Authority advises that, each week, it receives several enquiries about the waterproofing requirements for wet areas. Building elements in wet areas must be waterproof or water resistant in accordance with the National Construction Code (NCC) and must comply with Australian Standard AS3740 – Waterproofing of domestic wet areas.
Bathrooms, showers, laundries and toilets are considered to be wet areas within a home, and as such, the building elements in these rooms must be waterproof or water resistant. The NCC 2015 (Volume One – Table F1.7, and Volume Two – Table 18.104.22.168) provides details of the areas that are required to be water resistant or waterproof.
For bathrooms with timber floors (including timber sheet flooring such as particleboard or plywood sheet flooring), the entire floor outside the shower area must be waterproofed. Likewise, floor and wall junctions should be waterproofed whether the bathroom floor has timber or fibre-cement floors.
If concrete or compressed fibre-cement sheet flooring is used in wet areas, the floor must at least be water resistant.
Technical enquiries can be referred to the VBA to firstname.lastname@example.org or phone 1300 815 127.