How plaster walls are built
Before drywall became standard, walls were built from thin strips of wood, called lath, nailed across the studs with small gaps between them. Plaster was pushed through the gaps, where it curled behind the lath and hardened into "keys" that hold the wall on, then built up in two or three coats. Mid-century homes often have gypsum lath or veneer plaster instead. Knowing which you have matters for the repair.
Common problems
- Hairline cracks from normal settling and seasonal movement.
- Wide or recurring cracks, often over doors and windows, from movement in the structure.
- Loose or bulging plaster that sounds hollow when tapped: the keys have broken and the plaster is coming away from the lath.
- Holes from impact, old fixtures or plumbing and electrical work.
- Water damage, which softens plaster and can make paint bubble or flake.
Before you start: lead and asbestos
Most homes with original plaster are old enough to have lead paint. In homes built before 1978, federal rules require contractors who disturb painted surfaces to be lead-safe certified and to contain the dust. Some plaster, textured finishes and joint compounds from the middle of the last century also contain asbestos. A test costs far less than the problem of disturbing either without knowing.
How each repair is done
Loose plaster. Rather than tearing it out, the plaster is re-attached to the lath with screws and wide plastic plaster washers, often with an adhesive injected behind it, then the washers are skimmed over.
Cracks. The crack is opened slightly and cleaned, loose material removed, then bridged with fiberglass mesh tape and setting-type compound or plaster in thin coats. Setting-type compound bonds well to plaster; premixed drywall compound is more likely to crack again.
Holes. Small holes are filled in layers with setting compound. Larger holes get new lath or a piece of drywall shimmed to the depth of the surrounding plaster, then finished flush.
Walls with many cracks. A skim coat over the entire wall, or laminating with thin ¼-inch drywall, can be cheaper than repairing dozens of separate cracks.
Repair or replace with drywall?
Repair keeps the original walls, their sound-deadening mass and their trim details, and is almost always cheaper for localized damage. Replacing plaster with drywall means demolition, dust, disposal, and often new trim, because drywall is thinner than the plaster it replaces. For wall repairs in drywall homes, see drywall repair cost.
What plaster repair costs
| Job | Typical cost |
|---|---|
| Nail holes and hairline cracks | $20–$30 / sq ft |
| Average plaster repair | About $48 / sq ft |
| Large cracks or holes | $90+ / sq ft |
| Typical single repair | $307–$483 |
| Minimum charge, most contractors | $150–$250 |
Common questions
Can I use drywall compound on plaster walls?
Yes. Setting-type compound bonds well to plaster and is the usual choice for crack and hole repair. A bonding agent helps on very smooth or painted plaster.
Why do plaster cracks keep coming back?
Usually because they were filled without being bridged with tape, or because the plaster around them is loose. Re-attaching loose plaster and taping the crack stops most recurring cracks.
Can I hang pictures on plaster walls?
Yes. Drill a pilot hole first rather than hammering a nail, which can crack the plaster, and use a screw into the lath or a stud for anything heavy.
Related guides
Compiled from published 2026 national cost data (Angi, HomeAdvisor, Homewyse). Lead-safe requirements from the US EPA Renovation, Repair and Painting Rule. We update these figures as we complete jobs.