Tile over tile

It is not generally known, but tile CAN be installed over other tile! I have done it numerous times - on floors - showers - tubsplashes. There is no reason to believe it cannot be done as it is just another substrate. And the installer needs only the appropriate adhesive.

One of the logical restrictions is that the area to be tiled is restricted to where there is existing tile. To allow that there will be a significant difference in height. This is to suggest that if a floor is already down in ceramic, a new one can be installed on top of it BUT one cannot continue to an adjoining area as well since the new floor area would need to be appropriately raised to obtain the same height.

The advantage, of course, is the elimination of mess of tearout and the additional expense.