Should I repair or replace plaster walls?

Press gently on the plaster around the damage. If it is firm, repair it: fill cracks, tape stress cracks, and patch holes. If small areas are loose with sound plaster around them, a plasterer can screw them back to the lath with plaster washers. Cover or replace plaster damaged by long-term moisture, plaster that crumbles, and ceilings that sag across most of the room.

Is a sagging plaster ceiling dangerous?

Yes. When the keys that hold plaster to the lath break, the plaster comes loose, and if it is not repaired it can fall in chunks. Keep people out from under a sagging ceiling until it is fixed.

Can you put drywall over plaster?

Yes. Covering a room's walls with drywall over the plaster is $1,500–$4,000, and it creates far less dust and debris than tearing the plaster out. On a cracked or sagging ceiling with no moisture damage, plasterers often keep the old ceiling and fasten new lath and plaster over it.

What does plaster repair cost in 2026?

Crack and small-hole repair is $250–$800 for a room. Reattaching loose plaster with plaster washers is $500–$1,500 for a ceiling, and skim-coating a room's walls $1,000–$3,000. Covering a room's walls with drywall over the plaster is $1,500–$4,000, and tearing out a room's plaster and hanging drywall $2,500–$6,000, more when lead or asbestos has to be handled.

Repair or replace plaster walls?

Q: Does old plaster contain lead or asbestos?

The paint on it may contain lead. Under the EPA's Renovation, Repair and Painting rule, anyone paid to disturb painted surfaces in a home built before 1978 must be certified and follow lead-safe work practices. The rule generally does not apply to owners working on their own home, unless they rent out all or part of it, run a child care center there, or buy, renovate, and sell homes for profit. The National Park Service also warns that asbestos, used in the mid-twentieth century as an insulating and fireproofing additive, may be present. Have the paint tested, or assume it contains lead, and have the plaster tested for asbestos before a tear-out.

Cracked plaster in an older house usually needs a repair, not a tear-out. Plaster was the wall surface for nearly all buildings until the 1930s or 40s, and the National Park Service notes that it is often not as badly damaged as it first appears. The decision turns on one question: is the plaster still holding on to the wall?

How plaster holds on, and how to test it

Old plaster was troweled over strips of wood lath. It squeezed through the gaps and hardened into "keys" that hold it to the wall. When the keys break, the plaster comes loose and bows out, even if the surface looks fine.

Press gently on the wall or ceiling around a crack with a flat hand. If it is firm, the plaster is sound and the crack is cosmetic. If it moves, sounds hollow, or bulges, the keys have broken there.

Usually worth repairing

Hairline cracks in an otherwise sound wall. Fill them with joint compound or patching plaster.
Cracks running from the corners of doors and windows. Cover them with fiberglass mesh tape and joint compound.
Loose plaster with sound plaster around it. A plasterer can screw it back to the lath with plaster washers, then skim over the washers.
Holes, patched with new plaster over metal lath.

Usually worth replacing or covering

Plaster damaged by long-term moisture, once the leak is fixed. The National Park Service says partial or complete removal may be necessary when plaster is badly damaged, particularly by long-term moisture.
Plaster that crumbles when you press it.
Loose or sagging plaster across most of a ceiling. On a cracked or sagging ceiling with no moisture damage, plasterers often keep the old ceiling and fasten new lath and plaster over it. That creates much less dust than demolition.

A sagging ceiling is a safety issue, not a cosmetic one. If plaster that has lost its keys is not repaired, it can fall in chunks. Keep people out from under it until it is fixed.

Some cracks are a sign of something else. Diagonal cracks running in opposite directions can mean the house is settling. See our guide to foundation cracks.

Before anyone sands or demolishes it

Old plaster walls are usually painted, and the paint may contain lead. Under the EPA's Renovation, Repair and Painting rule, anyone paid to disturb painted surfaces in a home built before 1978 must be certified and follow lead-safe work practices. The rule generally does not apply to owners working on their own home, unless they rent out all or part of it, run a child care center there, or buy, renovate, and sell homes for profit. The dust is the same hazard either way. Have the paint tested, or assume it contains lead and follow the EPA's lead-safe practices for do-it-yourselfers.

The National Park Service also warns that asbestos, used in the mid-twentieth century as an insulating and fireproofing additive, may be present in plaster. Before a tear-out, have a sample tested.

What it costs in 2026

Crack and small-hole repair: $250–$800 for a room.
Reattaching loose plaster with plaster washers: $500–$1,500 for a ceiling.
Skim-coating a room's walls: $1,000–$3,000.
Covering a room's walls with drywall over the plaster: $1,500–$4,000.
Tearing out a room's plaster and hanging drywall: $2,500–$6,000, more when lead or asbestos has to be handled.

See our methodology for how we build these bands. Tear-out costs more than it looks: the dust and debris from a plaster wall are far heavier and messier than drywall.

The bottom line

Press on the plaster before you decide. Repair cracks, holes, and small loose areas in sound plaster. Cover or replace plaster damaged by long-term moisture, plaster that crumbles, and ceilings that sag across most of the room. Keep people out from under a sagging ceiling. In a house built before 1978, have the paint tested before anyone sands or demolishes it, and have the plaster tested for asbestos before a tear-out.