Plaster walls, generally found in older homes, are made from a cement-based mixture spread over thin strips of wood, called lath. The mixture grips the lath and dries to create hard, stiff walls. Plaster walls are durable, sturdy and will last for many years. Damage occurs to plaster from improper plaster formulation, accidents or cutting holes to gain access to plumbing pipes, electrical wires or adding insulation.
Things You'll Need
- Joint compound
- Flexible putty knife
- Fine-grit sandpaper
- Keyhole saw
- Hand-held broom
- Metal or fiberglass mesh
- Galvanized staples, screws or nails
- Plaster mix
- Bucket or trough
- Epoxy-based concrete bonding agent
- Self-sticking fiberglass mesh tape
- Safety glasses
- Dust mask
Break away small pieces of loose plaster from the edge of the hole with your fingers.
Fill the hole with joint compound. Apply the joint compound with a flexible putty knife and press the compound deeply into the hole. Build the compound up to 1/8-inch above the surface of the wall.
Allow the joint compound to dry completely, usually 30 to 60 minutes.
Sand the patch smooth with fine-grit sandpaper.
Plastering Large Holes
Cut the edges of the hole with a keyhole saw to form straight lines resulting in a square or rectangular hole. Brush away dust from the edges of the hole with a paintbrush or small hand-held broom.
Cut a piece of metal or fiberglass mesh to the exact size of the hole. Use galvanized staples, nails or screws to fasten the mesh to the thin wood strips.
Mix dry plaster mix with water in a bucket or trough until it forms a thick pasty consistency.
Apply a coat of epoxy-based concrete bonding agent to the edges of the hole, mesh and lath with a paintbrush.
Press the plaster into the hole with a trowel firmly to grip the mesh and lath. Apply additional layers as needed to build the plaster up to flush with the existing wall.
Drywall Patches For Plaster Walls
Cut the edges of the hole with a keyhole saw to straighten jagged edges and make the hole into a square or rectangle. Sweep the dust off the edges of the hole.
Measure and cut a piece of drywall to fit exactly into the hole. Secure the drywall to a wall stud or lath with drywall screws.
Apply a coat of joint compound to the edges of the patch with a flexible putty knife. Push the joint compound deep into the recesses and build it up to the same height as the existing wall. Apply a paper-thin layer of joint compound over the drywall patch.
Place self-sticking fiberglass mesh tape over the seams of the patch while the joint compound is still wet. Apply two thin layers of joint compound over the fiberglass tape and allow the joint compound to dry fully, typically one to two hours.
Sand the edges of the patch with fine-grit sandpaper to smooth and blend with the existing wall.