How to prepare walls for tiling

Tiles can be fixed to most walls as long as they are properly prepared. The walls must be suitably level, clean, dry and free of dust, grease or any loose material. All surfaces must be completely secure without any obvious movement and capable of carrying the additional weight of the tiles and adhesive.

When tiling onto walls you must consider the weight of the tiles. Our store teams can confirm the weight of the purchased tiles if you’re unsure. Ensure to include 3kg per m² in your calculation to allow for the weight of the adhesive and grout.

Plaster (Gypsum) skimmed walls or plasterboard has a maximum weight loading of 20kg/m2  whilst bare plasterboard can take up to 32kg/m2.

New backing coat and skim coat plaster must be allowed to dry for at least four weeks prior to tiling and a new plaster skim coat on top of plaster board must be allowed to dry for at least seven days prior to tiling.

All plaster/plasterboard surfaces should be primed with undiluted BAL Prime APD when using a BAL cementitious powder adhesive. If using a BAL ready mix adhesive then prime with BAL Prime APD diluted at 1:1 with clean water.

All surfaces must be completely dry prior to tiling.

Tiles can be fixed directly onto sand and cement renders up to a maximum weight loading of 40kg/m2; the render must be a minimum of two weeks old (three weeks for swimming pools) to enable movement caused by drying shrinkage to have taken place. It must be clean, dry and free from dust, laitance or any other contaminants which may act as a release agent, preventing the adhesive from bonding to the render.

If the render is dusty it should be thoroughly dry brushed with a stiff bristled brush and the dust removed from the surface prior to priming. When tiling with a cementitious-based tile adhesive, prime the render with one coat of BAL Primer or BAL Prime APD – diluted 1:1 by volume with water. Allow to dry before tiling.

Most bricks and blocks can be tiled directly onto up to a maximum loading weight of 40kg/m2 and provided they are sufficiently flat to receive the tiled finish. Lightweight and medium dense block-work must be primed with one to two coats of BAL Primer. In areas which will be subject to wetting, a render coat must be applied to lightweight and medium dense block-work. The primer must be completely dry prior to tiling.

Topps Tiles does not recommend tiling onto papered or painted surfaces. Paintwork, i.e. emulsion paint, distemper or limewash, is generally unsuitable for tiling. The paper or paint should be completely removed and substrate cleaned and primed before tiling. See more on tiling onto painted surfaces here.

Tile backer boards are really useful as they provide a clean and flat surface and allow a maximum weight loading of 200kg/m2. Ensure the board is correctly installed according to manufacturer’s specifications prior to tiling. Detailed information regarding preparing multiple substrates and tiling onto tile backer board can be found here.

Extra care must be exercised when tiling domestic showers. It is recommended in a power shower or wet room area to tank the walls and floor to ensure the room is fully waterproof. Various methods, such as a liquid membrane, BAL Waterproof Plus Kit, Laticrete Hydro Ban or a matting system Topps Waterproof Matting can be used and should be applied before tiling.

If you’re looking to tile over existing tiles you need to ensure the tiled wall can take the additional weight. As this limits your choice of tiles it’s often best to remove the existing tiles. If the weight is fine, ensure the existing tiles are completely clean, degreased and are firmly fixed to the wall.

For most surfaces we would recommend using the BAL Primer as it stabilises dusty surfaces and reduces the porosity of backgrounds. Never use PVA to prime a surface before applying tiles. When you treat a surface with PVA it only partly soaks in and sits on the surface of the substrate much in the same way as wallpaper paste. If PVA gets wet it becomes slightly live again, it doesn’t completely return to its liquid state but it becomes sticky. When you spread tile adhesive onto a wall, the water in the adhesive makes the PVA live and stops the adhesive from penetrating the substrate and providing a mechanical grip. Always use the appropriate primer for your substrate.

Now you've prepared your substrate, you're ready for tiling! Read our guide on how to tile a wall.