How to Cut Plaster Walls & Repair With Drywall

Tap on the plaster with a hammer to knock some plaster loose in the damaged area and create a hole. Pull out as much of the damage by hand, working your way to the left and right until you locate the wall studs to which the plaster lath is attached.

Clean up the hole and make straight edges. Score the plaster with a utility knife to form a square around the hole. Place the putty knife in the score and tap it with a hammer to knock the plaster loose to form smooth edges. Cut out the plaster on the sides to the midpoint of the wall studs.

Measure the opening and transfer the dimensions to a piece of drywall. Score the drywall with the utility knife and snap it along the edge of a table to remove the unneeded portions.

Place the drywall in the hole and attach it to the studs with drywall screws. Drill the screws through the edges of the drywall and into the studs.

Dampen the edges of the plaster where it meets the drywall. Spread a thin amount of drywall compound over the seams between the drywall and the plaster. Use a taping knife to spread it. Place a strip of drywall tape over the compound, and then cover it with a little more compound. Let the wall dry for at least 12 hours, and then sand the compound smooth.

Dampen the plaster along the wall around the repair area. Spread an additional layer of compound over the seams, and taper it down on the sides as you move away from the tape. Let this dry for another 12 hours.

Sand the wall smooth where the compound dried. Paint the wall with matching paint. Use a paintbrush in even up-and-down strokes.