DIY Repair Large Wall Holes
Also see:This method can be used to repair holes of about a square foot down to a few inches, in drywall and plaster walls only. This drywall patch would sag if used on a ceiling, causing a bulge in the finished repair. To repair large holes in ceilings, use the method on the next page.
The setting and drying times in these instructions assume the use of 30 minute setting–type joint compound like Durabond45® because it will work well for this repair. If you want to use a slower acting compound or ready–mixed drywall compound it will work but the mud must be allowed to dry completely between coats. For help mixing and handling joint compound, see the skim coating techniques on this page.
Cut a Square Hole
Using a framing square, mark the wall surrounding the damaged area to form a square or rectangle. This will make it easier to cut a new piece of drywall to fill the hole. Cut along the marks with a drywall saw or a drywall knife.
For wood lath plaster, cut the sand and putty coats away from the wood and use a drywall patch thin enough to fit over the wood and fill the hole without protruding above the surrounding surface.
If the damage is due to water or there's any other contamination present, seal the surrounding wall surface with a shellac–based primer–sealer and let it dry for about an hour before proceeding with the repair. Blisters may develop in the finished repair if contamination inhibits bonding between the existing surface and the new drywall patch and joint compound. Sealing the surface will prevent this problem.
Cut a Drywall Patch
Measure the hole and cut a piece of drywall to be about 2 inches wider and longer than the opening.
Turn the piece of drywall over and with a pencil, mark the location of the top, bottom and sides of the hole on the back.
Mark the drywall to be a little smaller than the opening in the wall. This will make the patch fit easily into the hole without forcing.
Draw a line connecting the marks on each edge to form a square on the back of the drywall patch.
With a sharp drywall knife, score along each line, cutting through the backing paper and just into the gypsum core.
Snap the drywall along one side at a time and pull the backing paper and gypsum core away, leaving the facing paper attached to the patch.
With all four sides removed the patch should look like the one here. Test the patch for size by placing it in the opening. Be sure it fits easily, trim the gypsum if necessary for a smooth fit.
Patch the Wall Hole
See the instructions for mixing and handling setting joint compound. Mix about a cup of the powdered compound as directed and then thin it with a little more water than recommended. This will make it easier to stick the new patch to the wall without ripping the drywall paper.
Apply a thick coat of the mixed mud around the perimeter of the hole. Let mud cover the inside edges of the hole as well.
Press the drywall patch into the opening. Lightly press the paper flaps into the mud so they make good contact. Push lightly on the center of the patch to be sure it is seated into the hole and level with the wall or slightly indented. Don't allow the patch to sit above the wall level. This will create a bulge in the finished repair.
Use a drywall joint knife to squeeze the mud from between the wall and the paper edges of the patch. Work around the perimeter of the patch, pressing the joint knife hard against the wall to squeeze all but a very thin coat of mud from between the paper and the wall. Stroke away from the center of the patch in a radial pattern around the patch.
Avoid repeated skimming in one place, the drywall paper will be softened by the wet mud and may tear. If this happens straighten out the tear and press it back in place lightly with the joint knife.
If the new patch is not level with the wall, gently push it to level or slightly below the surrounding surface before the mud sets. A slight depression will allow for building the wall surface up with the subsequent coats of mud. Allow the mud to set for about 30 minutes or more. Be sure the mud has set before continuing.
Skim Coat the Patch
Mix more mud and apply it over the entire patch and onto the surrounding wall. Hold the joint knife at about 30° and coat the patch with back and forth strokes.
Immediately go back and skim the excess mud off to leave a thin film over the patch and surrounding surface. Make parallel strokes from one side of the patch to the other. Ignore any ridges left by the edge of the blade, you will scrape them off when the mud sets.
Let the mud set for about 30 minutes and use the joint knife to scrape off any ridges. At this point the patch will still have a rough finish and will need a couple more coats of mud to smooth it out.
Mix and apply another coat of mud. Immediately skim the excess mud off, stroking in the opposite direction of the previous coat. If you skimmed the mud horizontally before, skim with vertical strokes this time. This will help to fill in any pits and help to smooth out an uneven surface.
Sand and Touch Up the Paint
Allow the final coat of mud to set and dry for at least an hour. Sand the repair, feathering the edges into the surrounding surface. Brush the dust from the repair and wipe with a damp rag to remove all joint compound residue before priming and painting.
If you are using flat latex finish paint, you can use it to prime the repair. If you are using semi–gloss or other shiny paint, prime with flat latex paint or a latex primer first.
