Wet Area
Building Code

Building elements in wet areas within a building must be protected with a waterproofing system. The waterproofing system in (1) must be either waterproof or water resistant in accordance with 10.2.2 to 10.2.6.

For a shower area with a hob, step-down or level threshold, the following applies: The floor of the shower area must be waterproof, including any hob or step-down (see Figure 10.2.2); and The walls of the shower area must be waterproof not less than 1800 mm above the floor substrate (see Figure 10.2.2).Wall junctions and joints within the shower area must be waterproof not less than 40 mm either side of the junction (see Figure 10.2.2). Wall/floor junctions within the shower area must be waterproof (see Figure 10.2.2). Penetrations within the shower area must be waterproof. A shower with a preformed shower base must also comply with the requirements of (1), except for (a) which is not applicable. Notes: Where a shower is above a bath or spa, use requirements for shower.

For concrete, compressed fibre-cement and fibre-cement sheet flooring, the floor of the room must be water resistant. For timber floors including particleboard, plywood and other timber based flooring materials, the floor of the room must be waterproof. Wall/floor junctions must be waterproof; and where a flashing is used, the horizontal leg must be not less than 40 mm.

For areas adjacent to all baths and spas, the following applies: For concrete, compressed fibre-cement and fibre-cement sheet flooring, the floor of the room must be water resistant. For timber floors including particleboard, plywood and other timber based flooring materials, the floor of the room must be waterproof. Tap and spout penetrations must be waterproof where they occur in horizontal surfaces.(2) For areas adjacent to non-freestanding baths and spas, the following applies: Walls must be water resistant (see Figure 10.2.4a and Figure 10.2.4b) to a height of not less than 150 mm above the vessel, for the extent of the vessel, where the vessel is within 75 mm of a wall; and for all exposed surfaces below vessel lip. Wall junctions and joints must be water resistant within 150 mm above a vessel for the extent of the vessel. Wall/floor junctions must be waterproof for the extent of the vessel (see Figure 10.2.4a and Figure 10.2.4b). For inserted baths and spas, the following applies: For floors and horizontal surfaces: Any shelf area adjoining the bath or spa must be waterproof and include a waterstop under the vessel lip. There are no requirements for the floor under a bath or spa. For walls: Waterproof to not less than 150 mm above the lip of a bath or spa. There are no requirements for the floor under a bath or spa. For wall junctions and joints, the following applies: Waterproof junctions within 150 mm of a bath or spa. There are no requirements for junctions and joints in walls beneath the lip of a bath or spa. Tap and spout penetrations must be waterproof where they occur in horizontal surfaces

For walls adjoining other types of vessels (e.g. sink, basin or laundry tub), the following applies: Walls must be water resistant to a height of not less than 150 mm above the vessel, for the extent of the vessel, where the vessel is within 75 mm of a wall (see Figure 10.2.5). Waterproof wall junctions where a vessel is fixed to a wall. Waterproof tap and spout penetrations where they occur in surfaces required to be waterproof or water resistant. For laundries and WCs, the following applies: The floor of the room must be water resistant. Wall/floor junctions must be water resistant, and where a flashing is used, the horizontal leg must not be less than 40 mm. For WCs with handheld bidet spray installations, the following applies: The floor of the room must be waterproof. Walls must be waterproof in WC area within a 900 mm radius from the wall connection of the handheld bidet spray device to a height of not less than 150 mm above the floor substrate; and water resistant in WC area within a 900 mm radius from the wall connection of the handheld bidet device to not less than 1200 mm above the finished floor level of the WC. Wall junctions within the WC area within 900 mm radius from the wall connection of the handheld bidet spray device must be waterproof. Wall/floor junctions within the WC area within 1000 mm radius from the wall connection of the handheld bidet spray device must be waterproof. Penetrations in the WC area must be waterproof.

For the purposes of this Part, a waterproofing system is deemed waterproof, if it complies with (2); or water resistant, if it complies with (3). For a waterproofing system required to be waterproof in accordance with 10.2.2 to 10.2.5, the materials nominated in 10.2.8 must be used. For a waterproofing system required to be water resistant in accordance with 10.2.2 to 10.2.5, the materials nominated in 10.2.9 must be used in conjunction with the materials in 10.2.10.

Where required to be installed in accordance with 10.2.2 to 10.2.6, materials used in wet areas forming a waterproofing system must be either waterproof or water resistant in accordance with 10.2.8 and 10.2.9.

The following materials used in waterproofing systems are deemed to be waterproof: Stainless steel. Flexible waterproof sheet flooring material with waterproof joints. Membranes complying with AS/NZS 4858. Waterproof sealant.

The following materials are deemed to be water resistant: For walls: Concrete complying with AS 3600, treated to resist moisture movement. Cement render, treated to resist moisture movement. Compressed fibre-cement sheeting manufactured in accordance with AS/NZS 2908.2. Water resistant plasterboard sheeting. Masonry in accordance with AS 3700, treated to resist moisture movement. For floors: Concrete complying with AS 3600. Concrete slabs complying with AS 2870. Compressed fibre-cement sheeting manufactured in accordance with AS/NZS 2908.2 and supported on a structural floor.

The following surface materials are deemed to be water resistant: For walls: Thermosetting laminate. Pre-decorated compressed fibre-cement sheeting manufactured in accordance with AS/NZS 2908.2. Tiles when used in conjunction with a substrate listed in 10.2.9. Water resistant flexible sheet wall material with sealed joints when used in conjunction with a substrate listed in 10.2.9. Sanitary grade acrylic linings. For floors, when used in conjunction with a substrate listed in 10.2.9: Tiles. Water resistant flexible sheet flooring material with sealed joints. Concrete treated to resist moisture movement. Explanatory information Sheet vinyl or linoleum would satisfy the requirements of this clause.

For the purposes of this Part, materials used in wall and floor substrates must comply with 10.2.9.

Where a floor waste is installed the minimum continuous fall of a floor plane to the waste must be 1:80; and the maximum continuous fall of a floor plane to the waste must be 1:50.

For the purposes of this Part, wall and floor surface materials must comply with 10.2.10.

Shower areas must be designed as either enclosed or unenclosed to include a floor waste with falls complying with 10.2.12; and with a stepdown complying with 10.2.15; or hob complying with 10.2.16; or level threshold complying with 10.2.17.

For stepdown showers, the highest finished floor level of the shower area must be stepped down a minimum of 25 mm lower than the finished floor level outside the shower (see Figures 10.2.15a, 10.2.15b, 10.2.15c and 10.2.15d).

Hobs must be constructed of masonry; or concrete; or autoclaved aerated concrete; or extruded polyurethane foam,in accordance with Figure 10.2.16. All gaps, joints and intersections of the hob substrate must be made flush before application of a membrane. Hobs must be adequately secured to the floor and sealed against the wall prior to applying a membrane. Timber must not be used for hob construction

For enclosed showers without a stepdown or a hob, at the extremity of the shower area, a waterstop must be positioned so that its vertical leg finishes where a shower screen is to be installed, not less than 5 mm above the finished floor level (see Figure 10.2.17); and where the waterstop intersects with a wall or has a joint, the junction must be waterproof.

Unenclosed showers must be constructed as follows: A waterstop must be installed a minimum horizontal distance of 1500 mm from the shower rose.The vertical leg of the waterstop must finish—flush with the top surface of the floor (see Figure 10.2.18); and where the waterstop intersects with a wall or is joined the junction must be waterproof; or the whole wet area floor must be waterproofed and drained to a floor waste as for the shower area. In the case of (1)(b)(ii)(B), at doorways, where the height of the tiling angle needs to be adjusted for tiling purposes, the angle must be fixed with a sealant compatible with the waterproofing membrane without damaging the waterproofing system.

Preformed shower bases must have an upturn lip (see Figure 10.2.19a and Figure 10.2.19b); and be recessed into the wall to allow the water resistant surface materials and substrate materials to pass down inside the perimeter upturn lip of the shower base (see Figure 10.2.19a and Figure 10.2.19b); and be supported to prevent distortion or cracking.

Baths and spas, except freestanding baths and spas, must have an upturn lip; and be recessed into the wall (see Figure 10.2.20); and have the water resistant substrate materials of the wall pass down inside the upturn lip (see Figure 10.2.20).

Where a screed is used in conjunction with a waterproof membrane, the waterproof membrane can be installed either above or below the tile bed or screed.

The substrate surface area where a membrane is to be applied must be clean and dust free; and free of indentations and imperfections.

Penetrations within shower areas must comply with the following: Penetrations for taps, shower nozzles and the like must be waterproofed by sealing with sealants; or proprietary flange systems; or a combination of (i) and (ii). The spindle housing of the tap body must be able to be removed to enable replacement of the washer without damaging the seal. The following must be waterproofed: All penetrations due to mechanical fixings or fastenings of substrate materials. Any penetration of the surface materials due to mechanical fixings or fastenings. Recessed soap holders (niches) and the like. Tap and spout penetrations on horizontal surfaces surrounding baths and spas must be waterproofed by sealing the tap body to the substrate with sealants; or proprietary flange systems.

Flashings must be installed in accordance with 10.2.2 to 10.2.5 and the following: Perimeter flashing to wall/floor junctions must have a vertical leg that extends a minimum of 25 mm above the finished floor level, except across doorways; and horizontal leg that has a minimum width of not less than 50 mm. Where a water resistant substrate is used in conjunction with a water resistant surface material, a waterproof sealant must be installed at the substrate junction at the wall/floor junction. Perimeter flashings at a floor level opening must comply with the following: Where the whole wet area floor is waterproof, at floor level openings, a waterstop must be installed that has a vertical leg finishing flush with the top of the finished floor level with the floor membrane being terminated to create a waterproof seal to the waterstop and to the perimeter flashing (see Figure 10.2.24). In any other case, at a floor level opening a waterstop must be installed that has a vertical leg finishing flush with the top of the finished floor level and waterproofed to the perimeter flashing. A vertical flashing, either external to the wet area or internal, must extend a minimum of 1800 mm above the finished floor level. Explanatory information Vertical flashing may be used as follows: External vertical flashing may be used with external membrane systems and installed behind the wall sheeting or render. They must have legs of sufficient width to allow the wall sheeting or render to overlap by not less than 32 mm. Internal vertical flashing may be used with both external and internal membrane systems provided each leg has a minimum overlap of 40 mm to the wall sheeting or render and where used with internal membrane, must extend vertically from the shower tray; and external membranes, must overlap the top edge of the floor waterproofing system by not less than 20 mm; and preformed shower bases or baths, must extend to the bottom edge of the wall sheeting or render

For hobless showers, or showers with hobs or stepdowns, the membrane must be applied over the floor and up the vertical face of the wall substrate to a minimum height of 1800 mm above the finished tile level of the floor.

Where wall sheeting is used with an external membrane system in a shower area it must be waterproof to prevent water movement by capillary action. Where water resistant plasterboard is used all cut edges that have the potential to be affected by water and moisture must be waterproofed, including the bottom edge over a preformed shower base.

Bond breakers must be installed at all wall/wall, wall/floor, hob/wall junctions and at movement joints where the membrane is bonded to the substrate. Bond breakers must be of the type compatible with the flexibility class of the membrane to be used. Explanatory information Typical details for bond breaker types are given in Explanatory Figure 10.2.27.

Where a shower has a hob the membrane must be brought over the top of the hob, down the outside face and terminate not less than 50 mm onto the floor (see Figure 10.2.16). Where the shower has a waterstop, the membrane must be brought to the top of the finished floor, except where it is under a framed shower screen where it must terminate not less than 5 mm above the finished tile surface (see Figure 10.2.17 and Figure 10.2.18).

Membrane drainage connections in concrete floors must comply with one of the following: A drainage flange must be installed with the waterproofing membrane terminated at or in the drainage flange to provide a waterproof connection (see Figure 10.2.29). Where a preformed shower base is used, provision must be made to drain the tile bed and provide a waterproof connection to the drain. For membrane drainage connections in other floors, a drainage flange must be installed with the waterproofing membrane terminated at or in the drainage flange to provide a waterproof connection (see Figure 10.2.29). Where a preformed shower base is used, provision must be made to drain the tile bed and provide a waterproof connection to the drain. Floor wastes must be of sufficient height to suit the thickness of the tile and tile bed at the outlet position. Explanatory information: Drainage flanges For membrane drainage connections in concrete floors: drainage flange may be either cast into the concrete slab or set into the top surface of the concrete slab or the tile bed. For membrane drainage connections in other floors: drainage flange may be either set into the floor substrate or the tile bed.

Where a preformed shower base is used, the drainage riser must be connected to the tray with a waterproof joint. Where an in situ shower tray is used, the membrane must be able to form a permanent waterproof seal to the drainage riser or drainage flange (see Figure 10.2.29).

Where the bottom of a door jamb does not finish above the floor tiling, the portion of the door frame below the floor tiling must be waterproofed to provide a continuous seal between the perimeter flashing and the waterstop.

For a shower with a hob, the shower screen must be installed flush with the shower area side of the hob or overhang into the shower area. For a shower with a stepdown, the shower screen must be installed flush with the finished vertical surface of the stepdown of the shower area. For a shower without a hob or stepdown, the shower screen must incorporate or be mounted on an inverted channel, positioned over the top of the waterstop, that defines the shower area. For bath end walls and dividing walls abutting a shower, the shower screen must be positioned so that the bottom edge within the shower area is either flush with the outside edge of the bath or overhanging into the shower area. Explanatory information A self-draining sub-sill is considered to be part of the shower screen.

The floor of a wet area containing a vessel must be graded to a floor waste to permit drainage of water. A floor need not be graded to the floor waste as required by (1) if all vessels are provided with in-built overflow protection or have a permanent open trapped connection to the plumbing and drainage system (such as a WC pan); or the floor waste is provided solely for the connection of plumbing fixtures and all vessels in the wet area are provided with in-built overflow protection or have permanent open trapped connection to the plumbing and drainage system (such as a WC pan). A floor of a wet area that is graded without ponding to a floor waste within the shower area will satisfy (1). The fall of the floor surface graded to the floor waste in accordance with (1) or (3) must be in accordance with 10.2.12.