AS 3740:2021 is the Australian Standard for waterproofing of domestic wet areas. Every bathroom, ensuite, laundry and powder room in Victoria has to be waterproofed to this standard. Here is what it actually says, without the jargon, so you can read your own quote and know whether it complies.
What AS 3740 actually requires
The entire floor of an enclosed shower must be waterproofed. Walls of the shower must be waterproofed to 1800 mm above the floor. The rest of the bathroom floor must be waterproofed if the floor is timber, particleboard, or above a habitable room, or if the bathroom is on a second storey.
Walls behind baths and vanities that abut a wet area must be waterproofed to 150 mm above the fixture. All penetrations (taps, wastes, mixers) need bond-breaker collars. All internal corners need bond-breaker tape or fillet.
The 2021 changes that matter
Hobless (curbless) showers now require a much more carefully detailed threshold — the membrane has to be turned down into a rebate or under a linear drain, and the fall has to be documented. Waterstops at doorways became explicit rather than implied. Compliance certificates became the industry expectation, not just a nice-to-have.
How to check your quote is AS 3740-compliant
Look for four things: named membrane product with a two-coat system, upturns specified (150 mm floor to wall, 1800 mm in the shower), penetrations detailed, and a compliance certificate on completion. If any of these are missing, the job is not compliant — full stop.