Our Canberra tiler says the new laundry does not need waterproofing because there is no shower in it. The certifier wants the floor treated anyway. What does the code require for a laundry?

The certifier is right. A laundry has its own line in the Housing Provisions, and a shower is not what switches it on. The floor of the room must be water resistant, and so must the wall/floor junctions. [2] "No shower, no treatment" is the misconception here.

What the code requires for the laundry room. Under 10.2.5(2), for laundries and WCs: [2]

• The floor of the room must be water resistant. That is the floor of the room, not just the area under the tub, and the clause does not make it depend on a floor waste.
• Wall/floor junctions must be water resistant, and where a flashing is used, its horizontal leg must meet a minimum width.

What the tub adds. A laundry tub is a vessel, so 10.2.5(1) also applies to the walls around it: [1]

• Where the tub is within 75 mm of a wall, the wall must be water resistant to a height of not less than 150 mm above the tub, for the extent of the tub.
• Where the tub is fixed to the wall, the wall junction must be waterproof.
• Tap and spout penetrations must be waterproof where they occur in surfaces required to be waterproof or water resistant.

Waterproof and water resistant are not the same thing. The Standard uses them as two separate grades, and it uses both inside the same clause. For a laundry the floor, the walls behind the tub and the wall/floor junctions only need to be water resistant. [1] [2] The tub/wall junction and the tap and spout penetrations need the higher grade, waterproof. [1] So the tiler is wrong that nothing is needed, but the certifier is not asking for a shower-grade result across the whole room either. Getting the grade right for each element is what settles the argument.

Where people go wrong. Waterproofing gets talked about as a shower issue because that is where the heaviest requirements sit. The laundry provisions are separate and apply on their own. Removing the shower does not remove the laundry from the code; it just means the laundry rules, not the shower rules, are the ones to meet.

Practical next step. Ask the certifier in writing which system they will accept for the floor and for the wall/floor junctions, and have the tiler confirm the tub position against the 75 mm and 150 mm figures before the wall is lined. Water resistant is achieved by specific substrate and surface combinations, and the qualifying materials are set out later in Part 10.2 of the Housing Provisions, so the tiler's proposed build-up can be checked against them rather than argued about on site.

ACT edition note. The ACT is on NCC 2022 with the ACT Appendix, but until 30 April 2027 you may instead elect NCC 2025 with its ACT Appendix. One edition must be nominated at lodgement and the two cannot be mixed. It makes no difference here: NCC 2025 carries the same laundry wording and the same 75 mm and 150 mm figures. [3] No ACT variation to these clauses was found in either edition, so confirm with your certifier before relying on the national text alone.