Tiling over a Tiled Shower Pan

Q:

I’d like to change the tile in my shower pan. Is there a way to do so without removing the existing tile? Neither the tile nor the drain leaks.

Rob Brenner, Hannibal, KS

A:

Tom Meehan, owner of Cape Cod Tileworks, replies: Absolutely. In fact, I recently completed a similar job. It’s a straightforward process that requires isolating the old tile with a waterproofing membrane, removing the old drain cover, and setting a new grate over the existing drain.

I isolate the old tile with Schluter-Kerdi membrane (www.schluter.com) set in a thin bed of latex-modified thinset. To get a good bond between the old tile and the thinset, I score the old tile and drain assembly with an angle grinder. Then I cover the entire pan with latex-modified thinset, making sure the membrane overlaps the existing drain flange. Once the thinset is down, I install the Schluter-Kerdi membrane and let it cure for about 24 hours.

1. Rough up the tile

Use an angle grinder equipped with a diamond blade to score the old tile. This creates a better bonding substrate for the latex-modified thinset.

2. Lay the waterproofing membrane

After spreading a thin layer of thinset over the old tile, install Schluter-Kerdi membrane. Trowel the membrane flat, and remove all excess thinset around the drain flange. Let the membrane set for 24 hours.

The key to this process is making sure that the new drain grate doesn’t sit above the new tile, so I install the tile and the drain grate at the same time. I use the top section of Schluter’s Kerdi-Drain two-part assembly. The assembly is designed to work with Schluter’s bonding flange, but I simply set it in thinset above the existing drain’s flange. Other drain grates might work, but this is the only one I’ve found that’s shallow enough to work in this application.

Using a grinder, I grind down the small knobs that protrude from the existing drain flange, and I lay a generous amount of thinset around the drain and around the grate. Then I set the grate over the drain, pushing down firmly with both hands to ensure a tight seal all around.

3. Lock the grate in place with thinset and tile

After applying thinset around the drain, press the grate in place until it sits flat. Next, I test-fit the new tile around the grate, adding or removing thinset until the tile is even with or slightly above the new grate. I proceed by tiling around the drain toward the walls. The key here is to ensure that everything pitches toward the drain. Once the thinset cures, I complete the job with grout followed by two coats of Miracle Sealants 511 Impregnator sealer.