Few things detract from the look of a well-tiled wall like a hole does. Not only is it attention-getting, it's an opportunity for further damage as the hole grows or moisture leaks into the wall beneath, weakening the bond of the remaining tiles around the hole. Repairing a hole in a tile wall should be a high priority project for any homeowner. The process is twofold: First you repair the wall, then you replace the missing tiles with tiles in the same style and colour. Once you complete the repair, the patched area should be indistinguishable from the surrounding tile.
Remove the grout between the tiles bordering the hole and the rest of the tiled surface, using a rotary tool equipped with a carbide blade. Run the tool over the grout, cutting through it to the surface below. Place a putty knife into the opened joint and slide it under the tiles bordering the hole. Pry these tiles slowly from the surface of the wall, taking care not to cause additional damage' you will reinstall them later.
Clear the mortar from the backs of the border tiles by rubbing it with sandpaper. Remove the mortar from the wall surrounding the hole by pushing the rotary tool along the surface.
Mix a solution of 1/4 cup trisodium phosphate (TSP) and 1 gallon of water. Dip a sponge into the solution, then scrub it on the surface of the wall surrounding the hole. Rinse the surface with clean water.
Examine the wall to determine the extent of the damage. Repair smaller holes -- up to the size of one tile -- by filling the hole with joint compound, using a putty knife. Cut a piece of fibreglass mesh about 1/4-inch larger than the hole. Cover the hole with the mesh, pressing the mesh into the joint compound. Wait for the compound to dry to the touch. Apply another coat of compound with the putty knife to cover both the hole and the surface immediately surrounding the mesh.
Repair a larger hole with a mesh repair patch. Cut around the perimeter of the hole with a sabre saw until you create a rectangular space. Place a series of plywood backer strips behind the hole. Hold the plywood strip in place with one hand while you screw drywall screws through the wall and into the plywood beneath to secure it in place.
Measure the dimensions of the hole and cut a piece of mesh repair patch to match. Place the patch into the hole atop the plywood strips. Fill the hole with joint compound. Cover the joints between the patch and surrounding wall with fibreglass mesh tape. Place another layer of compound over the patched area. Allow it to dry to the touch.
Sand the surface of the patch level with medium-grade sandpaper. Retain some of the texture of the patched area so the new tiles will adhere.
Mix a batch of thin-set mortar, following the manufacturer's directions. Wait 10 minutes for the mortar to hydrate -- absorbing all the water added to the mixture -- then stir it slightly.
Apply the mortar to the patch and surrounding empty space, using the flat side of a trowel. Tilt the trowel 45 degrees and run it over the mortar to raise ridges.
Set the border tiles you removed in Step 1 into the mortar. Place spacers between the tiles to recreate the joints removed by the rotary tool. Place new tiles in the empty space where the hole was. Follow the same spacing as the border tiles. Allow the mortar to set overnight.
Remove the spacers from the tile joints. Mix a batch of grout following the manufacturer's instructions. Fill the joints with the grout, using a grout float. Push the grout over the face of the tiles into the joints, filling them completely.
Wipe the surface of the grouted tiles with a damp sponge to remove any excess grout. Wait two hours. Wipe the tile surface with a clean, lint-free towel to remove all trace of the grout on the tiles. Allow the grout to set for the length of time directed by the manufacturer.
Apply a sealer to the grout and tiles to protect the tiles from moisture and damage. Allow the sealant to dry for 48 hours before using the tile surface.
Use a grout and tile sealant specifically made for your type of wall tile.