DIY Plaster Repair: An Easy-to-Follow Guide for Homeowners
Plasterwork is a beloved and often elaborate decorative feature in many older homes, and the distinct textures and look of real plaster cannot be fully replicated with paper-faced, gypsum-filled wallboard, or drywall. Over time, however, many houses experience common problems with their plaster such as cracks and sagging areas. Fortunately, plaster repair is relatively simple and easy to do with the right tools and materials, such as plaster washers.
The first step in repairing plaster is to familiarize yourself with it. Plaster is largely made of lime, water, and sand which is held together with the support of wood lathing. As houses move and shift, and build up moisture, the plaster may separate from the wood lath and form cracks. When cracks are small, they can be reattached with plaster washers spaced a few inches apart. To avoid cracking the plaster, use a 1/8-inch diameter Carbide-tipped masonry bit to create pilot holes for the screws. With large loose areas, install the washers in circles starting where the plaster is most firmly attached and working inward.
To ensure the plaster is secure along any cracks, install screws on both sides about an inch away from the crack, apply joint compound, then reinforce it with self-adhering fiberglass tape. A 5-inch taping knife can be used to apply the compound in two stages, then scratch the surface of the first coat so the second coat will adhere better. For larger holes, use a scrap of drywall to fit the hole and fasten it with screws before applying compound.
To prevent the plaster and wood from drawing moisture out of the compound too quickly, mist the area with water prior to patching. When the compound has dried, use a pole sander with very fine (150-grit) sandpaper to smooth the surface. Apply two or three additional coats of compound, allowing drying time between each and feathering each one out slightly further than the last.
When dealing with sagging plaster, the first step is to figure out the area where it has become detached. Secure the plaster in place with screws and washers, and if extra pulling and holding power is required, attach it into the joists or rafters.
In summary, repairing plaster can be done in a few simple steps. Begin by removing any loose chunks of plaster and reattaching it with plaster washers. Fill small holes with joint compound, then reinforce with self-adhering fiberglass tape. Apply multiple coats of compound with a taping knife and mist the area with water. After patching the area, use a pole sander to smooth the surface. To secure plaster in areas of sagging, securing it with screws and washers can help to provide extra support.
