Repair Hairline Cracks in Plaster Walls

If your home has plaster walls, you can resign yourself to patching before every paint job. Harmless cracks will return with regularity no matter how often you fill them. Watch, though, for loose or crumbly cracks, holes, and bulges; these may mean you have a leak. If you have a leak, fix it before doing any work on the walls.

Time: 20 to 30 minutes.

Skills: Basic skills.

Tools: Hammer, chisel or old screwdriver, putty knife, taping knife, old toothbrush, sanding block, and a sponge.

Plaster Patching Materials

Dry-mix joint compound is strong, making it a good choice for wide cracks and holes.
Vinyl surfacing compound is soft and flexible. Use it for narrow cracks or holes.
Patching plaster or gauging plaster creates a genuine plaster surface, but it takes time to learn how apply it correctly.
Latex/silicone caulk stays flexible and so can accommodate shifting cracks.
Aerosol crack seal is ideal for small cracks. Spray it just before priming.

Step-by-Step

1. Widen the crack.

Widen the crack to about 1/4 inch with a chisel and blow out any loose plaster.

2. Fill with vinyl spackle.

Wipe crack with a dab of surfacing compound, pressing it into the fissure. Press the spackle into the crack, mounding it up a bit. Allow to dry, then sand or sponge it smooth.