We’ll take you through what you need to know in order to make a wet room waterproof. If you are experienced at DIY then you may feel confident enough to take this task on, but if not then we highly recommend to call in a professional.
Important notes for making a wet room waterproof
Tiles and waterproof boards are water resistant, but if you’re going to create a wet room you need to be 100% sure that the joints between the tiles do not leak and cause damage to the fabric of your building.
In a wetroom, you’ll need a central drain in the floor for the water to drain away, so you’ll need to be careful that this area is sealed and watertight.
An alternative to tanking and tiling the walls in a wet room is to use shower panels. These are uPVC panels that slot together into pre-formed channels. They can be fitted to existing plastered walls, timber or steel studwork, or stuck on top of tiled bathroom walls.
Learn how to make a wet room on a concrete and timber floor.

Making a wet room waterproof
1. Ensure surfaces are flat and smooth
Ensure surfaces are stable and reasonably flat and smooth. Remove old tile, adhesive and crumbling plaster etc. before using primer. Fill in any holes and make sure the filler has had enough time to dry.
2. Apply the first coat of primer
Apply the first coat of primer to the wall using a brush and work in vertical strokes ensuring an even coverage. Work along the room from the floor to the ceiling.
3. Leave the primer to dry
Allow the primer to dry for at least 6 hours.
4. Apply the second coat of primer
Apply a second coat of primer and work horizontally across the walls, working from the bottom to the top.
5. Apply waterproof tape
Ensure the primer is dry before moving onto the second stage, which is to apply the waterproof tape to the joints in the room, which includes vertical joints between the walls and the horizontal joints between the walls and floor. This prevents water from seeping in-between these areas. When taping the walls, work from the bottom up.
6. Tape the joists between the floor
If you have a timber floor you’ll need to tape the joists between the floorboards.
7. Seal around the drain
Use the self-adhesive membrane to seal around the drain by cutting a hole the correct diameter for the drainage pipe. Any other pipes that come into the room should also have the sheeting cut around them.
8. Ensure the tape is securely stuck
Use a roller to ensure the tape is securely stuck and there are no air bubbles in the seal between the membrane and the floor.
9. Seal the joints
Seal the joint between the walls and floor and use a roller to ensure the tape is firmly stuck.
10. Apply the rubber membrane to the floor
Apply the liquid rubber membrane to the floor first and allow to dry.
11. Apply the rubber membrane to the walls
Next, paint the walls with the rubber membrane.
12. Apply the liquid membrane
Apply two coats of the liquid membrane at right angles to each other. Allow to dry for 6 hours between coats.
13. Leave to completely dry
When the second coat has been applied and allowed to dry, you can then tile your wet room.
Hi, I’m Liz, an interiors blogger. My main focus area is the bathroom, where I aim to inspire anyone who’s planning and designing a new bathroom – you’ll find plenty of tips, how-to guides and a wealth of ideas!