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Do you need to waterproof entire bathroom?

Author

Sarah Smith

Published Jan 16, 2026

If the bathroom floor is above ground level, or made of timber, plywood or particleboards, the entire bathroom floor must be waterproofed.

How do I waterproof my whole bathroom?

  1. Step 1: Check surface adhesion. ...
  2. Step 2: Clean work area. ...
  3. Step 3: Apply corner pieces. ...
  4. Step 4: Apply tape for corners and edges. ...
  5. Step 5: Waterproof plumbing fittings. ...
  6. Step 6: Apply membrane on walls. ...
  7. Step 7: Correction and finishing. ...
  8. Step 8: Apply membrane of floor for bathroom sealing.

Do you waterproof bathroom walls?

Bathroom walls must be waterproofed up to a height of 150 mm. The step down from the shower to the floor must be waterproofed to a height of at least 100 mm. If the bathroom is not on the ground floor, the entire bathroom floor must be waterproofed.

What needs to be waterproofed in a bathroom?

The full floor within the shower room must be waterproofed. The hob or step down onto the bathroom floor must be waterproofed by at least 100mm. The entire floor where the bathroom is located must be waterproofed (second story and higher). The walls inside the shower must be waterproofed by at least 150mm.

Do I need to tank my whole bathroom?

If you're creating a wet room, then you'll need to tank the room. Waterproof wall panels for bathrooms are highly effective but you need 100 per cent assurance that no water can escape, as the damage could prove costly.

34 related questions found

Do you need to waterproof bathroom walls before tiling?

Water can creep through the tile joints and cause damage to the walls behind the tiles. This is why it's important to waterproof the background that you're going to be tiling onto.

Do I need to waterproof shower walls before tiling?

You should waterproof all the shower walls before tiling. A tile backer or cement board is typically not waterproof, albeit many are water-resistant. The most effective and reliable solution is a separate waterproofing membrane on primed shower walls before tiling.

How many layers of waterproofing do I need for my bathroom?

Waterproofing a bathroom.

Two coats are needed, each taking 24 hours to dry. Extra sealant may also be needed once the tiles are down. It's a job that can take up to four days, so allow plenty of time.

Does a separate toilet need to be waterproofed?

Unless the toilet is inside a bathroom, then there is currently no requirement in the AS3740 or the NCC/BCA to waterproof the toilet. You should however make sure that the perimeter floor/wall junctions are fully caulked with a good quality SMX or polyurethane caulk.

Do you waterproof under a shower base?

In bathrooms, all timber floors including particleboard and plywood are to be fully waterproofed over their entire surface area, excluding the area under a preformed shower base or built-in bath, whether the shower is enclosed or not.

How do you tell if a bathroom has been waterproofed?

Check Your Bathroom Tiles

Keep in mind, bathroom tiles are not totally waterproof. But they are specially designed for wet environments and to repel water so it travels straight down the drain. If the tiles becomes cracked or loose, it leaves the surface exposed to water penetration.

Does a wet room need tanking?

Tanking is the most important part of any wet room installation and it's crucial that high-quality waterproofing products and systems are used to ensure optimum performance and longevity.

How do you waterproof a bathroom floor before tiling?

Seal with Silicone

  1. Using a caulk gun and silicone seal, fill the seams between the floor and the wall.
  2. Fill any cracks in the floor as well.
  3. Cracks and gaps will attract moisture, so sealing them completely is an important step in making sure your floors are entirely waterproofed.
  4. Allow to dry for 24-hours.

How do you waterproof a floor before tiling?

In general, you should always waterproof a bathroom floor before tiling. Use a waterproof membrane to protect the substrate from water and moisture. Seal the joints of the waterproofing membrane using waterproof sealing tape. I also recommend using the sealing tape on the corners near the bath and shower.

Do you need to waterproof a bathtub?

Baths with an integral vertical upstand lip along the side of the bath walls require to be recessed to enable the junction to be waterproofed. Baths without an integral edge require full waterproofing of the walls and floor area around and under the bath.

When should you use waterproofing?

Typically, extensive waterproofing measures are applied during construction to ensure that moisture is controlled at the initial stage. Waterproofing can also be done after a building has been built to solve problems as they arise.

How long does waterproofing a bathroom take?

Water Proofing

A waterproof liquid rubber membrane is painted onto areas that are likely to see water to create a sealed area. Waterproofing takes at least 24 hours to completely dry, this can be at least a 2-day process for 2-3 coats.

How long does waterproof membrane last?

While basic waterproofing membranes should last at least ten years, they can last much longer given the right choice and circumstances. Conversely, poor quality waterproofing will rarely last the distance.

Do I need waterproof membrane in bathroom?

Without adequate membrane, water damage is likely to occur. And, what's more, it will probably go unnoticed for a considerable period of time, which means the problem will worsen without you realising. Make sure you put thorough waterproofing in place from the start, to avoid issues in the future.

Is waterproofing a shower necessary?

If you are concerned about the tile grouting that could be penetrated by water when using the shower, then it is important to install a waterproof membrane. This material will act as protection and water will be diverted toward the drain which could also prevent the formation of mold.

How do you seal bathroom walls before tiling?

Fresh drywall needs up to a month before it's ready for tiling, but when the time comes, you won't have to tape the joints. All you'll need to do is apply a skim coat and sand. Once done, clean the surface from dust, dry any signs of moisture and apply the adhesive.

Do tilers do waterproofing?

In many cases, your bathroom renovator or tiler will include waterproofing in their quote. Otherwise a dedicated waterproofer will need to come in. Waterproofing products are typically sheets or a water based, flexible, high performance polyurethane membrane which is painted onto a surface.

Do you have to waterproof a concrete bathroom floor before tiling?

Cement is a very porous material and can easily absorb water. Therefore, any concrete that may come into regular contact with water, such as under tile or a pool, will need to be waterproofed. If cement is not waterproof, it can cause issues with the mortar used between the tiles.

Is Tanking necessary for shower?

If it is a wet room with a tiled floor and no shower tray then yes it needs tanking. In a nutshell, the tanking process is where tape is applied to the corners and joins and a waterproof coating is painted on. It is not always necessary to tank the floor if a shower tray and enclosure are being installed.