Knowledge base

In this guide we answer the simple question of ‘can you tile over tile?’

Tiling over the existing tiles may be considered a shortcut, but it can be a practical option for those wanting an efficient kitchen or bathroom redesign. There are several important things to consider before you start your project.

• The existing tiles must be soundly bonded to the walls. If the old tiles de-bond from the wall and fall off, then so will the new ones so make sure the old tiles are well fixed. One way to check is to gently tap them. If it sounds very hollow then they are likely not well bonded. Pay particular attention to wet areas which are more likely to have problems.
• The existing tiles need to be clean and free of grease or other contaminants which could affect the bond of the adhesive used for the new tiles. Use sugar soap or a suitable degreaser to clean the surface before tiling.
• One thing to consider is the aesthetics. Tile over tile can be noticeable around the perimeters of a room such as coving, door frames, shower fittings and especially if the room is only half tiled. This is unlikely to be a problem unless you chose to finish off the top with a tile trim, you can’t put the trim behind the original tiles so this may leave an unappealing finish.
• Determine the original substrate before tiling. Most background substrates such as plaster and plasterboard have a recommended weight limit per m². Skimmed plasterboard can only take around 20kg/m². If you have a bumpy white tile (20×25) along with adhesive and grout, you will have a weight of approx.14kg/m² on your bathroom wall. With this in mind, you’ll only have an allowance of 3kg/m² for tiles after adhesive and grout which if surpassed may cause structural failure – this will limit your choice of new tiles. If you are looking to use larger, heavier tiles, you will likely need to remove the old ones first.