How to Replace the Backboard Behind Shower Tiles

Turn off the water supply to the shower. Put the stopper in the drain or plug the drain with a rag. This will keep the pipes from getting clogged with construction debris. Remove any loose tiles by hand if they are very loose or with the utility knife if they need encouragement. Remove plumbing fixtures. Some fixtures have screws that must be removed to take off the handles. The tub spout often screws off by twisting the spout to the left.

Score a line through the drywall with a utility knife around the tiled area of the shower. Cut deeper with each pass of the knife until you have cut through the drywall. Use the prybar and pull the tiled walls down. Clear away any nails or screws from the old walls off the studs. If you plan to reuse the tiles, each one will have to be removed from the wall and all of the thinset has to be scraped from the back of each tile.

Measure the exposed area. Cut the cement board to fit by scoring it with the utility knife and snapping it apart. Cover the exposed studs with the cement backboard. Attach with screws using the drill. Screws need to be placed every eight inches along the studs. Doing one wall at a time, apply a coat of thinset to the cement board. Place the waterproof membrane on the thinset and press firmly into place with a clean trowel or grout float. Repeat for remaining walls, cutting openings through the membrane for the plumbing fixtures.

Working in small batches, apply thinset to the waterproof membrane. Install tiles onto the wall, pressing firmly into place to ensure good adhesion. Start with the bottom tile row using 1/8-, 1/16-, or 1/32-inch spacers between the tiles. The size of the spacer depends on manufacturer guidlines and personal preference. Repeat until the shower is fully tiled. Trim tiles to go around pipes with the tile saw or tile nippers. Take care not to leave too large an opening; otherwise the beauty rings on the fixtures will not cover the hole. Let the area dry for at least 24 hours.

Apply grout with the grout float to the dry tiles. Work the grout into the joints as much as possible. Wipe away excess grout with a clean sponge. It is helpful to have a bucket of clean water nearby to remove the grout from the sponge. Once the shower is grouted, continue to clear away the excess grout. Keeping your sponge clean will make this process go faster. Let the grout dry for 24 hours.

Install the plumbing fixtures. Take care not to over-tighten the fixtures, or the tiles and grout may crack. Turn the water back on.