How to Replace a Missing Tile in the Shower

Assess the damage. Feel each tile to see if it is loose. Often, the tiles closest to the floor are the ones most likely to need grout repair or to come loose from their mastic.

Pry off the loose tile with a putty knife. Take care not to damage the tile. If other, nearby tiles show signs of being loose, pry them off as well.

Check the drywall behind the tile. If it feels mushy and shows signs of being wet, you should replace it. Cut it away from the studs with a drywall saw. Pull nails with a pry bar or hammer. Measure the opening left by the drywall. Cut a piece of cement backerboard, which is more water resistant than drywall, to fit into the opening. Attach the backerboard to the studs with galvanized screws.

Use a grout saw to remove the grout from the edges of all of the tiles around the opening. Remove any caulking.

Scrape off any mastic that remains on the back of the shower tile using a putty knife. If it doesn't come off easily, boil water. Set the tiles into the hot water for a few minutes. Remove the tiles with tongs. Scrape off the loosened mastic with a putty knife. Use a utility knife to scrape off any grout that remains around the perimeter of the tiles.

Spread mastic onto the wall using a notched trowel. Carefully set the tiles back in position on the shower wall. Take care to maintain straight grout lines. Allow the mastic to dry three days before proceeding.

Select grout that has latex listed as an ingredient because it is more water resistant. Mix grout according to package directions. Force it into the grooves surrounding the tiles with a grout float. Wipe off any excess grout from the face of the shower tile with a clean, damp sponge.

Insert a tube of silicone caulking into a caulk gun. Cut the tip of the caulking off with a utility knife. Run a bead of caulking along the edge of the shower to seal any openings. Skip this step if the tiles you replaced weren't on the edge of the shower wall.