Before beginning the work of installing the ceramic tile floor, assess the work area. What one is looking for is asbestos. If the work area was built during the 1970’s or earlier, the chances of asbestos being present is very high. Asbestos was used extensively in the construction trade until the late 1970’s. Asbestos is the chief cause of a form of lung cancer known as mesothelioma. When disturbed, its fibers get into the air which is breathed. Precautions need to be taken to insure one does not breathe those fibers.
Next, the foundation on which the ceramic tile is going to be put on needs to be assessed. There are certain foundations which are not suitable for ceramic tile flooring installation. They are cushioned vinyl flooring, any kind of particle boards, plywood, OSB (Oriented Strand Board), tongue and groove planking and hardwood floors. Concrete is a suitable foundation for ceramic tile flooring installation.
If the bathroom is in a foundation home, plywood may be the sub flooring and one will have no choice but to install the tile flooring on it. If that is the case, then the choice is to put a membrane between the ceramic tile and the plywood which will decrease the likelihood of moisture getting into the plywood.