If you are planning to transform a bathroom into a wet room in your home here are the basic tasks to tackle first to ensure the space is properly waterproofed.
Turning an ordinary bathroom into a wet room can transform everyday bathing into a luxurious experience. Depending on the fixtures, fittings and accessories you choose you could create the effect of a luxury spa within your own home.
A wet room is a completely waterproof room, which is not the same as simply a fully tiled room, but similar to tanking that would be done to fully waterproof a basement. Waterproofing different surfaces and parts of a bathroom require a different approach so you will need to know the different types of waterproofing methods and also understand the sorts of problems that can arise in the areas most prone to leakage.
Start with some straightforward tasks to prepare the room before tackling the job.
Once the walls are prepared you will need to waterproof them using the method most suited to the substrate.
Rendered walls are suited to a number of different waterproofing techniques. Specialist waterproof matting (such as that made by Shluter) can be fixed to the walls or a waterproof coating can be applied directly to sound render, or tile backer boards can be fitted on top of the rendered surface.
If your walls are stud partitions walls, plasterboard, plywood, plaster, brick or blockwork then you will have to attach tile backer boards, which are usually 10mm – 12.5 mm thick. Tile backer boards are limited to a maximum weight of tile plus adhesive so this will affect your choice of tile. Check with both your board and tile supplier to make sure you have a board that will support your preferred tiles.
If the substrate is new plywood it must have been allowed to acclimatise to the environment for at least 24 hours before beginning the waterproofing process.
Each tile backer board must be sealed around the edges with silicone sealant before fixing the next board. Once all boards are fixed, cover all the joints with polyester tape – this is available as part of the BAL WP1 Waterproofing Kit – and then skim with a cement based tile adhesive. Where there are gaps due to pipes, drains and shower fittings also use silicone sealant covered with polyester tape to seal the gaps; these are the places most likely to cause a leak in your wet room.
As with walls for a wet room, the floor needs to be waterproofed in different ways depending on the type of floor. Before beginning the waterproofing process double check the location and fitting of your shower tray and drain. When replacing a traditional bathroom with a wet room you will need to ensure that the finished floor height is where you expected it to be. The floor tile thickness, adhesive, tile backer board and waterproof matting will all contribute to raise the floor level so if you want it to be at the same level as outside the room then you may need to lower the floor before work begins.
Your bathroom floor is most likely to be concrete screed or floorboards. If you have floorboards then check that they are clean, dry and firm – screw down any that are loose. Stick a waterproof membrane (such as G-Mat, which will also prevent movement in the wooden floor from transferring through to the tiles) to the floor with a flexible thin-bed adhesive. Then seal all the joints with polyester tape, paying particular attention to corners and the areas around protruding pipes. Floor tiles can be laid directly onto the waterproof membrane.
A tile backer board serves the same purpose as a waterproof membrane – it is fully waterproof and is more suitable for uneven floors with gaps or cracks so is more commonly used when creating a wet room from an existing bathroom in an old property. It is glued to the floor with a tile adhesive and additionally screwed in place if the substrate is a timber floor.
Next time read more about grouting, shower trays and underfloor heating for wet rooms…