Drywall Repair for Large Holes in Walls and Ceilings

Repairing wall holes in drywall and plaster can be done in a number of ways. For small holes of a couple of inches or less, a fiberglass mesh patch can be covered with a few coats of mud. Larger holes will require the replacement of the missing drywall or plaster. The following method can be used to repair large holes up to a couple feet in both walls and ceilings.

The setting and drying times in these instructions assume the use of 30 minute setting–type joint compound like Durabond45®. When using a slower acting compound or ready–mixed drywall compound increase these times by double or more. For help applying joint compound using the techniques on the Skim Coating page.

Using a straight edge, mark the wall surrounding the damaged area to form a square. 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 knife. For plaster with wood lath, use a reciprocating saw to cut cleanly thru the wood strips. Keep the saw base pressed firmly against the wall to avoid blade vibration that would crack the plaster. If there are studs or joists within a couple of inches of the damaged area, cut the wall material back to expose enough of the framing to fasten the new drywall patch.

If no framing is handy, use this method to add improvised framing. Measure the opening of the squared hole you created. Cut two pieces of wood such as a 1x3 or 1x4, to 6 inches longer than the opening. Insert one of the wood strips into the hole and hold it tightly against the inside of the wall. Using a screw driver or drill–driver, turn a 1 5|8 inch drywall screw thru the gypsum board and into the wood strip. With lath plaster drive the screw thru the wood lath and into the new wood. Bore a pilot hole first and use a longer screw if necessary for thick plaster walls. Sink the head of the screw to just below the wall surface.

Fasten the strip at the top and bottom. Make sure the wood is firmly attached to the inside of the wall. Attach the second wood strip using the same method.

If there's any contamination around the hole, seal the wall surface with a shellac–based primer–sealer and let it dry for about an hour before proceeding with the repair. Bubbling may develop in the finished repair if contamination prevents bonding between the wall and joint compound.

Cut a new piece of drywall to fit the hole and attach it to the new framing. With thick plaster walls where the hole is deeper than the drywall thickness, stack two pieces or shim the framing out until the patch is level or slightly indented in the wall.

If holes in drywall have ruffled paper edges use a sharp drywall knife held at an angle to cut along the seams between the patch and the wall. This will eliminate any bulging in the finished repair caused by the raised paper edge. Tape the seams using fiberglass mesh tape. Overlap the ends of the tape.

Apply a thick coat of mud over the mesh tape using the drywall finishing techniques here. Hold the joint knife at a 30 degree angle and skim the excess mud from the seams and return it to the pan. Press down with the joint knife hard enough to remove all but a very thin coat of mud. Don't try to cover the tape with the first coat of mud. It will require a few more to build a smooth patch.

Let the first coat of mud set for about 30 minutes and then lightly sand the tape with 120 medium grit sandpaper to remove any raised fibers. Next, mix and apply a thick coat of mud over the tape and the rest of the patch. Skim off the excess using strokes that are perpendicular to the first. If the first strokes were vertical, use horizontal strokes this time. This will help to fill in any irregularities and smooth the surface.

Allow the mud to set for about 30 minutes and lightly sand the tape again. Mix and apply a third coat of mud stroking perpendicular to the last. By now you should have a fairly smooth surface. If not, allow the mud to set and apply another coat. Keep building on the repair in this manner until you have a smooth surface.

Allow the final coat of mud to set and dry for at least an hour. Use 120 grit medium sandpaper to sand the repair lightly, feathering the edges into the surrounding surface. Brush any dust from the repair before priming and painting. If you are using flat latex finish paint it is self–priming. If you are using semi–gloss or other shiny paint, prime the patch with flat latex paint or a latex primer first.