DIY Repairing Torn Drywall Paper
Drywall paper can be damaged when a wall is gouged while moving furniture or other common household activities. Water can also damage drywall paper, causing the surface to pucker and ripple. This can happen when removing wallpaper with a liquid stripper or due to a leaking pipe or roof.
The most important part of repairing damage like this is sealing it so it doesn't absorb any moisture from the repair compound and touch-up paint. If you don't seal the surface, the repair process will cause the undamaged layers of paper to bubble and ripple again, and no amount of sanding will fix the problem. Use the following procedure for a trouble free repair of torn drywall.
Cut Away the Damage
Cut all the torn or puckering paper away from the gypsum. If only the first few layers of paper are affected, cut down to the first, undamaged layer. Otherwise, remove all the damaged and peeling paper from the gypsum core.
Cut cleanly around the perimeter with a sharp drywall knife or a razor blade. Tilt the blade out a little to cut at a slight angle through the paper. Then gently peel the rough fringes of loose paper free, leaving a solid surface behind.
Apply a Sealer
Cover the exposed gypsum and surrounding wall with a thick coat of oil or shellac primer-sealer. Stir the sealer or shake the can first to be sure it's mixed well and then apply two, very thick coats with a brush. Let the primer dry for about an hour between coats, and let the final coat dry completely before proceeding.
Flatten the Paper Fibers
When the second coat of sealer is dry, use a joint knife to smooth out the raised paper fibers so they don't interfere with the repair compound. Go over the surface once or twice with the blade in a downward stroke to flatten the fibers out.
Apply a Coat of Joint Compound
Mix some setting-type joint compound and use it to cover the damage. Apply a thick coat over the whole area holding the joint knife at an angle to "butter" the surface with back and forth strokes. Leave about 1|8in of mud over the damage and the surrounding drywall.
Immediately skim the excess mud from the surface to leave a thin coat covering the damage. Hold the knife at a 30° angle and press down hard, but not hard enough to dig into the surface, as you skim from one side to the other. Scrape the collected mud from the knife onto the rim of a mud pan and finish skimming in parallel strokes. Clean the knife off after each stroke to keep the mud from spreading to unwanted areas.
Ignore any ridges left between the blade edge, these will be removed after the mud has dried. Around the perimeter of the patch, skim the mud as thin as possible to help blend it into the surrounding wall. Let the mud set for about 30 minutes or until it has hardened.
When the mud is dry, scrape off any ridges using the joint knife to cut them off with upward strokes. If necessary, use medium grit sandpaper to lightly sand the whole patch to smooth out any other bumps or protrusions. At the edges of the patch, sand to feather it with the surrounding surface.
Apply a Second Coat
Wipe the sanding dust off with a damp rag and apply a second coat of mud, skimming in the opposite direction from the first coat. If you skimmed the first coat vertically, apply the next with horizontal strokes. This will help to level out an irregular surface.
Let the mud dry and if necessary, apply another coat to build up a patch that hides the damage and smoothes out the wall. As before, scrape off any ridges first and sand if necessary, before skimming the patch again. Stroke with the knife in the opposite direction from the previous application.
Sand and Touch Up the Paint
Let the final coat of mud dry well and then sand it using light pressure in wide back and forth strokes to smooth and blend the surfaces. Along the edges, sand harder to feather the patch with the wall surface but avoid digging into the surrounding, sound drywall paper. Wipe the sanding dust away with a damp rag or sponge being careful not to wipe away the new joint compound.
Let the moisture from the rag dry and prime the patch. If you are using flat latex finish paint, it will be self-priming. If you are using semi-gloss or other shiny paint, prime with flat latex paint or a latex primer first before touching up the wall paint.