How to Patch Plaster

In this video, This Old House general contractor Tom Silva explains how to patch plaster.

Steps for patching plaster walls

1. Measure area of plaster wall that’s loose or damaged and needs to be replaced.
2. Cut a drywall patch slightly larger than the damaged wall section.
3. Hold drywall patch against plaster wall, and mark its outline with utility knife.
4. Using a utility knife, score the plaster along the patch outline.
5. Pry off the loose plaster with a painter’s tool; clean up the debris.
6. Set the drywall patch against the wall and secure it with 1 ¼-inch drywall screws.
7. Cover the seams around the patch with adhesive-backed nylon joint tape.
8. Apply a thin coat of joint compound to the taped seams and to screw heads.
9. Allow compound to dry, then sand lightly with 150-grit sandpaper.
10. Apply a second, slightly wider coat of joint compound to the seams.
11. Allow second coat of compound to dry; sand with 150-grit sandpaper.
12. Apply a third, even wider coat of joint compound to the seams.
13. Smooth dried compound with 320-grit sandpaper.
14. Finish the wall with a coat of primer and two paint topcoats.

Tools