Plaster is a thin layer of mortar applied over the masonry surface
Lath is a wood strip that’s covered with plaster. John Romans of John Romans Construction, Upper Arlington, Ohio, notes that cracks at door openings, around doorways, in hallways, near corners, or beams are usually stress cracks caused by the foundation shifting or structural movement. It can happen during renovations or because of a bad foundation.
He says that cracks at the corners are often caused by a leaking roof, pipe, or other place where water can flow. When you have water damage to plaster walls, you’ll see that the plaster will separate from the lath, causing a bulge. The area becomes soft when the application is applied over drywall. Both cases will show a stain with a brown tint.
Shapiro says that you should repair all defects 漆喰 immediately if they occur. It isn’t as simple as just filling in cracks on drywall. Romans says, “I’ve been unable to find a sealant that works for small hairline cracks.” We permanently remove the gaps. Plaster repairs may require tricky trenching.
When the compound has dried, apply a feather coat (bead coat) to the outer side of the tape. It should be approximately 6 inches wide. Putty knives should sit flush against the wall and tape. Before you apply the final coat, knock off heavy pieces. Romans says the trick to using drywall compound is not applying too much per coat. Less is better. “You can add more compound, and sanding is much easier.”
Plaster can make it difficult to hang pictures and other items. Shapiro says that the surface beneath bounces back when you strike plaster with a hammer. This can result in severe damage to the whole wall. Even if it doesn’t break, paint could bubble over and cause a dent the size of a golf ball.
Coombs recommends using an anchor and screw system when hanging heavy items like flat-screen televisions. She says that toggle bolts and molly bolts are the best anchors for plaster walls. Both are made from metal and provide additional support for heavy objects. “I’ve used [toggle] to hang large artwork in an old house, but there wasn’t any crumbling.” If necessary, use a stud-finder to find the stud.
Shapiro recommends repainting if your plaster has an old, cracked shine. A matte paint will minimize the defects. Before you repaint an old application, it is essential to consider the color that was previously applied. It is possible that the old paint was oil-based. To use water-based painting, you will first need to prime the surface.
Coombs says that cleaning plaster walls does not differ from other wall types. Only the surface texture is different, requiring more care because plaster can easily crack. She says first to vacuum them using the dust brush attachment, but if it is still dirty, you should use a damp, warm cloth with water and soap.