What Is AS 3740?
AS 3740-2021 is the Australian Standard for waterproofing of domestic wet areas. It is referenced by the National Construction Code (NCC) and sets the minimum requirements for waterproofing membranes in residential bathrooms, showers, laundries, and other wet areas. In Queensland, compliance is enforced by the QBCC through the building approval and inspection process.
Key Requirements Under AS 3740
The standard specifies several critical requirements: shower floors must be fully waterproofed with membrane turning up walls to a minimum 1800mm height, bathroom floors outside the shower must be waterproofed with membrane turning up walls to a minimum 150mm height, all internal corners and junctions must be treated with reinforcing, and waterproofing must extend into the waste outlet. Penetrations for pipes and fixtures must also be sealed.
Waterproofing Zones
AS 3740 defines different waterproofing zones within a bathroom: the shower zone requires the highest level of protection, the wet zone (rest of the bathroom floor) requires floor waterproofing with wall turn-ups, and areas adjacent to baths and basins have specific requirements depending on configuration.
Compliance in Queensland
In Queensland, waterproofing must be carried out by a QBCC-licensed contractor. A waterproofing certificate must be issued before tiling commences. Building certifiers may inspect the waterproofing as part of the building approval process. Non-compliant waterproofing can result in defect notices and required rectification.
Why Standards Matter
Compliance with AS 3740 protects homeowners from water damage, ensures resale value is maintained, and provides legal protection if issues arise. When you request quotes through our platform, all contractors we connect you with are QBCC-licensed and experienced in AS 3740 compliant installations.