Removing wall tile can leave minor to severe damage to the underlying wall surface. Ceramic tile is installed with one of two types of adhesive: glue-based adhesive, called mastic; or cement-based adhesive called thin set. If thin set is used, the damage can be severe. If the underlying wall is a cement-type board, you may have to replace it -- depending whether you are going to paint it or install new tile over it. If the wall is going to be painted, the cement board should be removed and replaced with a drywall that is moisture-resistant to achieve professional results.
Scrape the wall with a floor scraper, plasterboard knife or putty knife to remove leftover adhesive. Be careful not to gouge the plasterboard too much. Vacuum or sweep the floor of any debris.
Dust off the wall with a broom or small hand-duster to remove any loose debris. Vacuum or sweep the floor to clear it of any debris.
Inspect the wall for any major holes. Most holes can be filled with joint compound, using a plasterboard or putty knife, and covered with a piece of joint tape. Repair holes larger than a golf ball by inserting a small piece of plasterboard, then applying the joint compound and joint tape. Allow the plasterboard compound to dry according to the manufacturer's directions.
Inspect cement-board walls for major damage if you plan to install tile again. Repair small holes with thin-set mortar; consider replacing the cement board if it has holes larger than a golf ball.
"Skim" the wall with coating of joint compound to achieve a smooth surface if you plan to paint the wall, rather than tile it. Fill the plasterboard pan with joint compound. Begin applying the compound to the wall with an 20 or 25 cm (8 or 10 inch) plasterboard knife. Spread a thin coat, just thick enough to cover the damage. If part of the same wall did not have tile, feather the joint compound into that area, reaching about 30 cm (12 inches) past where the tile stopped. Continue applying joint compound until all the repaired areas are covered.
Sand the wall after it has dried, using a sanding pole loaded with sandpaper, or sanding by hand. Sand the repaired wall everywhere the joint compound was applied, until you have a smooth, continuous surface.
Examine the wall. Apply more joint compound to any areas that are not satisfactory, using the process you followed in Step 5. Texture the wall to match the adjoining walls before painting.
You can buy or rent a floor scraper at a hardware or tool-rental shop. The tool has a 7.5 or 10 cm (3 inch or 4 inch) razor blade on the end opposite the handle. Keep the work area clean. Mix a little water with the joint compound to make it easier to spread. Clean up any spilt joint compound with a sponge before it dries. Use fast-setting joint compound to speed up the drying time between coats. A fan can also accelerate drying times.
Use dropcloths to protect the floor. Wear a dust mask when sanding. Use caution when using the floor scraper and/or the razor knife, as they are very sharp.