Saint Gobain Weber talks tiling over tiles

When tackling a refurbishment project, it can be a pain to remove the existing tiles before laying new ones, adding time and effort to the project. So can you tile over tiles? The answer is yes, but there are a few things to keep in mind when tiling on top of existing tiles. Here’s Saint Gobain Weber’s advice…

1. Pick which tiles to use

When tiling onto walls, it’s important to consider the surface behind the tiles and how much weight it will be able to carry. The most common background for tiles is plasterboard which can hold around 32kg/m², allowing for 3.5kg of adhesive and grout, and 28.5kg of tile per square metre.

Skimmed plasterboard, however, can only take around 20kg/m², so you’ll only have an allowance of 16kg/m² for tiles after adhesive and grout. With this in mind, consider the existing tiles – if the old tiles are quite heavy already, this will limit your choice of new ones. If you are looking to use larger, heavier tiles, you will likely need to remove the old ones first.

2. Prepare existing tiles

It’s important to first check that the existing tiles are well-bonded to the substrate. If not, the new tiles could cause the old ones to come loose. If the old tiles are suitably fixed, you can now proceed to preparing them for the job. If not, unfortunately, they’ll need to be removed.

Before beginning, check that the tiles are level. A grinder must be used to flatten any areas which stick out from the rest of the
surface. If the existing tiles have been sealed, the sealer will need to be removed for the adhesive to stick to the tile. Finally, the existing tiles need to be cleaned thoroughly and all dust removed. This is a crucial step as the new tiles may fail to adhere if the old ones aren’t suitably cleaned.

3. Fix new tiles

When the surface is ready for tiling, spread a layer of flexible adhesive such as weberset SPF  or weberset rapid SPF  onto the
surface of the existing tiles. If the new set of tiles are particularly large or are stud-backed, an additional layer of adhesive on the back of them may be required.

If tiling onto a heated floor, a flexible tile adhesive is a must to allow for expansion and contraction of the surface beneath the
tiles. A quartz tile will require an ultra-flexible S2 tile adhesive, such as weberset pro lite – rapid.

4. Finish with grout and sealant

Finish the job by filling the joints with a suitable tile grout such as weberjoint premium which is available in a range of 18 colours. Use weberjoint silicone sealant (colour-matched to our full range of grout colours, as well as clear option) to seal the edges.