Bathroom Waterproofing in SA: What the Rules Require

Bathroom stripped back to brickwork, timber framing and new plumbing rough-in during a renovation by ASP Build & Co, Adelaide

Every new or renovated bathroom in South Australia has to meet the wet-area waterproofing requirements of the National Construction Code (NCC). For a house, that means following the ABCB Housing Provisions for wet areas, or those provisions together with Australian Standard AS 3740 Waterproofing of domestic wet areas. In the shower, the floor must be waterproof and, under NCC 2022, the walls of the shower area must be waterproofed to at least 1800 mm (ABCB, Waterproofing in houses).

Waterproofing is the part of a bathroom renovation you never see, and the part that does the most damage when it fails. Here is what the rules cover, how a proper job is sequenced, and what to ask whoever renovates your bathroom or ensuite.

Why the code cares so much

The ABCB explains that the NCC waterproofing provisions exist to stop dampness and water from wet areas causing health risks or damaging the building. A failed membrane rarely shows up straight away. Water tracks into wall frames, the slab or the room next door, and by the time tiles lift or a skirting swells, the damage behind them is usually well advanced.

What the NCC requires, in brief

Under NCC 2022 there are two ways to comply for a house: follow Part 10.2 of the ABCB Housing Provisions in full, or follow its key clauses together with AS 3740 (ABCB). Either way, the requirements set out what must be waterproof or water resistant in each zone of the room:

The shower area: a waterproof floor, and waterproof walls to at least 1800 mm above the floor, with wall junctions, wall-to-floor junctions and penetrations (like tap and shower outlets) sealed.
Outside the shower, around baths and spas and other areas such as near basins and laundry tubs each have their own requirements.
Falls to floor wastes: NCC 2022 made it mandatory that if a floor waste is installed, the floor is graded towards it.
Level-entry and unenclosed showers have their own specific construction requirements.

South Australia also has its own variations to the wet-area and floor waste clauses, listed in the SA schedule of the Housing Provisions (ABCB, Schedule 8 South Australia), so a builder working to interstate habits can get it wrong. The ABCB has also published NCC 2025; which edition applies depends on when your work is approved, and your builder or certifier should confirm it.

Frameless walk-in shower with linear floor drain, wall niche and large-format tiles in a bathroom renovated by ASP Build & Co — A walk-in shower with a linear drain. Getting the falls right before tiling is what makes it work.

How a proper wet-area job is sequenced

Strip back to the frame and slab (like the photo at the top of this page), so the condition of what's behind the old tiles is known, not guessed.
Fix what's found: damaged framing, failed sheeting, old leaks.
Rough-in plumbing and electrical so every pipe and cable that passes through a wet zone is in place before any membrane goes on.
Set the falls in the screed so water runs to the waste.
Membrane, with the junctions, corners and penetrations treated properly, and cured as the product requires.
Tile, grout and seal, then fit off fixtures.

Older bathrooms and asbestos

SafeWork SA lists the bathroom as one of the most common places to find asbestos inside homes built or renovated before the mid-1980s, along with the laundry and kitchen. If your bathroom is original to an older home, have suspect sheeting tested before demolition, and don't sand, drill or break it (SafeWork SA).

What to ask before you renovate

Which compliance path will you use: the Housing Provisions in full, or the Housing Provisions with AS 3740?
Who installs the membrane, and what product and documentation will I receive?
How will the falls be set, and where will the floor waste go?
How will a level-entry or walk-in shower be detailed?
Are you licensed? You can check a builder's licence on the Consumer and Business Services register (SA.GOV.AU).
Is the quote itemised, so I can see demolition, waterproofing, tiling and fixtures separately?

How we approach it

We waterproof and tile wet areas to standard, the first time, because it's the part of a renovation you can least afford to get wrong. As a licensed builder (BLD 360698) we manage the whole bathroom: design, demolition, waterproofing, plumbing, tiling, fixtures and cabinetry, with electrical done in-house by ASP Electrical Installations. See our bathroom renovations page for recent work, including ensuites and walk-in showers. We renovate bathrooms across the north, including Elizabeth and Gawler.

Common questions

How high do shower walls need to be waterproofed in SA?

Under NCC 2022, the walls of the shower area must be waterproofed to a height of at least 1800 mm, and the shower floor must be waterproof. Check with your builder or certifier which edition of the NCC applies to your job.

What is AS 3740?

AS 3740 is the Australian Standard for waterproofing domestic wet areas. Under NCC 2022 a house can comply by following the ABCB Housing Provisions for wet areas in full, or by following key clauses of those provisions together with AS 3740.

Does my bathroom floor need to fall to a floor waste?

The NCC does not always require a floor waste outside the shower in a house, but NCC 2022 says that if one is installed, the floor must be graded towards it. South Australia also has its own variation on floor wastes, so ask your builder how it applies to your layout.

Do you renovate ensuites as well as main bathrooms?

Yes. We renovate main bathrooms, ensuites and powder rooms, from compact ensuite renovations to complete bathroom remodels, all to the same waterproofing standard.

Sources

Rules and published figures checked on 5 October 2026. Third-party cost ranges are not ASP Build & Co prices; we quote every job individually after a site visit.

Bathroom waterproofing in SA: what the rules require