Can I tile over existing ceramic tile?
This is done regularly where there is not a floor height or wall thickness limitation and where the existing tile is well-bonded. To insure a good bond to the existing tile, certain procedures need to be followed; these are described in the TCNA Handbook in detail TR712 and TR713.
Note: Not all thin-sets (nor polymer modified thinsets) are capable of bonding directly to tile. Please consult the grout and mortar manufacturers specified for their recommended thinsets. Also, depending on the tile already installed, in some cases the tile must be mechanically abraded to insure a good bond – this is usually best determined with a “bond test.”
Caution: Mechanical or chemical abrasion to tile can release fine particles which could cause harm if inhaled or ingested. Mineral analysis of the tile and glaze should be performed before performing any operation. Appropriate safety equipment should be worn at all times. There are many labs including the TCNA lab that can provide toxic metals analysis as well as shear bond testing.