Published on December 4th, 2012 | by Henri0
Tiling over existing ceramic tile
Q. I would like to tile over existing 4-1/4″ x 4-1/4″ ceramic tiles with a different style/color ceramic tiles in a bathroom. The walls are sound and solid in the tub area, etc. and I would like to avoid the mess and inconvenience of tearing out the walls if possible. Is this something than can be done and if so, what wall preparation needs to be done and what adhesive should I use? But if it can’t or shouldn’t be done, why not?
A. Yes, it can be done. Slightly roughen the gloss on the existing tiles with an abrasive masonry carbide sandpaper or diamond disk, using a disk sander. You don’t need to sand the tiles into oblivion – only enough to break the sheen.
There are two ways to proceed from there: 1) You can set new tiles with a top- quality thinset adhesive over the roughed-up tiles, or 2) The better way is to apply 1/4-inch thick cement backer board to the tiles over a bed of thinset and to screw the backer board to the studs through the tiles. Set the new tiles onto the backer board with thinset. This is the safest way to do the job to ensure that there will not be any potential failure in the future.
You didn’t said if the walls are tiled throughout the bathroom (not just around the tub), if the tiles go to the ceiling or stop at six feet in the tub area and to wainscot height elsewhere, or if the tiles are set in mud or mastic. A mud job is trimmed with bullnose tiles, as it is 1/4-inch thicker than the wall finish. So you have to make sure that you can get bullnose trim that will cover the extra thickness regardless of the way you choose to install the new tiles.
If the existing tiles are set in mastic over the wall finish and are trimmed with clamshell tiles, you can get bullnose trim to compensate for the thickness of the existing tiles (and the backer board, if you use it) where the new tiles meet a wall. Or you can use a wood trim for a very attractive effect.by