Older homes use a combination of wooden slats and plaster to create interior walls. Although this was an effective way of finishing walls, the plaster can and does crack as the years pass. If you have a plaster wall in your home with cracks and holes in it, you could hire a contractor to repair them. Or, if you prefer to do it yourself and save money, you can patch the damaged areas using plaster of Paris.
Remove loose, cracked plaster from around the damaged areas using the soft brush or putty knife. Vacuum up the debris.
Insert the blade of the putty knife into the holes and expand them to a minimum of a 1/4-inch wide. This allows the plaster of Paris to better repair the holes. Make holes on the inside of the wall larger than holes on the outside.
Sand the edges of cracks and holes with the sanding pad. Brush away sand and loose bits of plaster.
Apply the bonding agent to the surface of the wall's damaged areas and the inside edges of cracks and holes using the putty knife.
Cut pieces of fibreglass mesh tape large enough to cover each crack and hole. Place the tape over the bonding agent and press it into the wall. Allow the bonding agent to dry according to product directions.
Prepare a batch of plaster of Paris according to product directions. The amount needed depends on the size of the cracks and holes you need to repair. Only mix a small amount at a time since it dries quickly.
Apply the plaster of Paris to the spaces inside the wall of the hole or the lines of the crack using the blade of the putty knife.
Cut additional pieces of fibreglass mesh tape large enough to cover each crack and hole. Place them on top of the plaster.
Texture the surface of the plaster to match the texture of the rest of the wall. If you want a smooth look, use the blade of the putty knife. If you want a textured look, use a sponge. Do all of your texturing while the plaster is still wet.
Paint the wall after the plaster has completely dried. Drying times vary based on the amount of plaster used; however, 24 hours is usually sufficient.