It is always ideal to tile onto a completely flat, well-cured concrete subfloor, however, this is not always possible, particularly when renovating a house. Luckily, it is possible to tile onto an existing floor, but you need to ensure that the proper preparation is in place.
Many tile installation problems occur due to the lack the proper substrate preparation. If you have no other option than installing tiles over another type of material, make sure you verify the following:
- Ensure that the existing tiles are not loose or chipped as this can prevent proper adhesion.
- It is extremely important to level the surfaces. You can level the surface using a grinder, sander or a tile level system.
- Create a rough surface to improve bonding. The existing surface needs to show some sort of roughness that will facilitate the bonding between the new adhesive and the old surface.
- Vacuum and wash floors thoroughly to remove all dust particles and debris from the surface.
- Use epoxy or other adhesive materials recommended for this type of installation and surface. These can help you avoid common tile installation problems later.
Various floor types
Tiling over a wooden subfloor – Make sure there is no moisture or water affecting the wood members and apply thin-set adhesive and install backer board. Use leveling compound to level the surface so it can minimize cracks in tiles over time.
Tiling over an existing tiled floor – Be sure to break or create a rough surface so the adhesive creates proper bonding between both surfaces. If possible, remove the tiles or at least be sure to create that rough surface.
Tiling over hardwood flooring – This is not the best option and one very common mistake. If possible, don’t do it. If you don’t have another option, remove the polyurethane membrane of the hardwood flooring to create a better bonding surface. Before starting, verify the condition and spacing of the joints as it might change from older to newer construction. Also, use a modified thin-set type of mortar for better results.
Tiling over vinyl floor – In situations on which the vinyl floor has been installed over concrete, take extra time to make sure the vinyl is clean and ready to receive the thin set mortar.