Improperly peeling wallpaper off a wall often causes deep gouges in the drywall underneath. Even small gouges and tool marks in drywall can show up after applying new wallpaper or paint to the walls, resulting in an amateurish-looking finish. Fixing the drywall gouges will give the wall's finish coat a smooth and even surface to bond to. A well-blended texture completely hides the drywall repair on painted walls; walls with wallpaper do not need this extra step.
Allow the drywall enough time to dry after you've removed all of the wallpaper. Most wallpaper removers spray the wallpaper with a water and soap mixture, or a water and enzyme mixture, before peeling the wallpaper. Both solutions must dry completely.
Mix drywall joint compound in a bucket with water until it has the consistency of cold butter. Use the drywall joint compound manufacturer's recommended "base coat" water-to-compound ratio, as stated on the joint compound's container. Generally, premixed compound needs 1 cup of water per gallon of compound, and dry powder compound mix requires approximately one part water to one part powder mix. Use a 4-inch drywall knife or a margin trowel to stir the joint compound.
Fill the gouge with the wet drywall joint compound. Use the 4-inch drywall knife to push the joint compound into the gouge.
Blend the joint compound into the drywall surrounding the gouge, using the drywall knife. Do not worry about tool marks in the drywall joint compound. Fill all of the gouges with the drywall joint compound. Let the joint compound dry. Use the joint compound manufacturer's instructions to determine the drying time.
Remove the ridges and valleys from the dried drywall joint compound, using sandpaper. Press the sandpaper lightly against the compound and sand in circular motions.
Mix drywall joint compound mix and water in a bucket, using the manufacturer's "skim coat" instructions. Use either the 4-inch drywall knife or a margin trowel to stir the mixture. Skim coats usually have a slightly thicker consistency than soup.
Apply the skim coat to the drywall's gouge patches, using an 8- or 12-inch drywall knife. Feather the skim coat into the drywall. Allow the skim coat time to dry before continuing.
Smooth the patches over the gouges with sandpaper. Use circular motions while sanding.
Clean the drywall dust from the work area with a vacuum. After you've cleaned up the mess, the wall is ready for new wallpaper.
Spray a small section of drywall with a can of aerosol drywall texture. Compare the texture's pattern to the existing texture on the wall. Turn the knob on the top of the can to adjust the texture pattern so it matches the existing pattern.
Spray the drywall patches with the aerosol drywall texture. Feather the new texture into the existing texture. Allow the new texture enough time to dry, according to the instructions on the can, before you continue.
Paint the patch and texture with a drywall primer. Most home improvement stores with a paint department can add colour to the primer so it matches the finish coat of paint; this helps darker colours blend together. Failure to use primer will leave dull spots in the finish coat of paint.