Yes, once again, the preparation of the surface to receive the new application of tile is important to the overall tile installation. It is very easy to remember, if the base material is unstable or compromised in anyway, the installation of whatever type of tile over the top of this compromised surface, will be equally compromised. Cracks will simply transfer up to the new surface and any spalling or deterioration of the existing surfaces will cause the new material to improperly bond to the existing surfaces, causing problems and constant maintenance issues.
We have discussed the proper preparation of the existing surface as well as the need to visually inspect the existing surface, to identify the capability of the new installation to both bond and be properly supported by the existing surface.
If there is any concern regarding the integrity of the vinyl, linoleum or wood existing flooring, the best method to ensure proper installation of the new tile application, is to remove the existing material. However, if this is not an option and the existing surface, must remain in place, then the installation of a larger tile, stone or rigid masonry material is recommended. There is an innate ability for a larger piece of slate, stone, tile, etc., if properly installed, to span cracks, or compromises in a sub-base material. It is important to ensure that the entire tile has a consistent layer of adhesive under the tile. This is performed by using a deep toothed trowel to install the thin set, under the new tile. The larger the tile, the more square inches of bearing is presented to the sub surface, therefore the tile or stone itself, will provide a bridging effect over a compromised base layer.