Floor Tile

Preparation is critical. If you don't take your time during this phase you will be retiling sooner than you want. In general, it is best to remove whatever floor is currently in place and start with the sub-floor. The surface should be smooth, clean and level. If there are holes or depressions in the subfloor they should be filled using a self-leveling compound. For the most common floors, the following is recommended:

Ceramic Tile:
It is possible to tile over existing tile but not recommended. One problem is the difference in height between the new floor and adjoining rooms. If you decide to tile over existing tiles, sand the existing tiles with a coarse-grit sandpaper to increase adhesion between the adhesive and the new tiles.

Wood:
If you are tiling over a plank or strip floor, simply install cement backerboard over the floor.

Vinyl or Linoleum:
It is acceptable to tile over these surfaces. Simply install cement backerboard over the existing floor. If you elect to remove the flooring, make sure that it does not contain asbestos. If you are unsure, call your local health department for instructions. If the mastic will not come up with a scraper you might try a heat gun to soften it. Just make sure that you have adequate ventilation as the mastic may contain some nasty chemicals.

Concrete:
Make sure that the floor is fully cured and level. If the floor is not level you may have to use some self-leveling filler.

After the surface preparation is finalized, clean the floor with a damp sponge. Make sure that you have plenty of clean water and rinse the sponge often. This will help improve adhesion.