Installing ceramic tile to drywall commonly requires one of two adhesive types. The first is mastic, a glue-based adhesive; the second is thinset, which is cement-based. The installation process is the same regardless of adhesive type. Both adhesives cover the wall in a thin layer, with the tiles placed onto the wet material to adhere to the wall as the material dries. Removing both the tiles and the layer of adhesive tends to damage the surface of the walls. Before remodelling the walls, repairing this damage is necessary. The repair process differs according to the level of damage, but when completed, the walls are once again ready for whatever improvements you wish to make.
Place a dust sheet at the base of the wall to collect fallen debris. Wear protective long-sleeved clothing, work gloves, safety goggles and a face mask to avoid cuts from debris or breathing in particles during the repair process.
Remove all traces of mastic or thinset adhesive from the wall using a putty knife. Place the knife against the wall at a 45-degree angle and, pressing it firmly, scrape along the surface of the wall, getting the edge of the knife between the adhesive and the wall and prying it upward. Remove the adhesive pieces by hand when it fails to fall off. Take care not to gouge the surface of the wall while scraping away adhesives.
Wipe the wall with a stiff-bristle brush to remove any debris.
Fill in small holes in the wall, 2 inches across or smaller, with joint compound. Push the compound into the hole with the putty knife until the compound is level with the wall’s surface. Scrape the top of the patch with the edge of the knife to create a smoother surface.
Repair large holes in the wall, more than 2 inches in diameter, by placing a piece of drywall, cut to fit the hole with a utility knife, into the hole and then covering the drywall patch with a layer of joint compound.
Cover the patched areas with joint tape. Allow the joint compound to dry according to the drying time suggested by the compound manufacturer.
Skim the entire wall with joint compound to repair small flaws left from the tiles and to create a smooth surface. Place joint compound into a drywall tray. Apply a thin layer of joint compound over the wall using a drywall knife. Cover the entire tiled surface, including the patched and taped areas. Feather the sides of the damaged area to adjoining wall surfaces, overlapping the adjoining surfaces by 12 inches, to create a continuously smooth wall for repainting. Allow the compound to dry.
Use a sanding pole to sand the surface of the compound smooth. If the sanding thins the skim layer down to the old surface, reapply more compound, allow it to dry and then sand again to complete the wall repair.
If you’re retiling the wall, replace the damaged surface rather than repair it to create a strong, sturdy subsurface.