Plaster Wall Repair in San Antonio

Plaster repair from a crew that lives in joint compound

A lot of drywall companies will not touch plaster, and a lot of painters just fill a crack and paint over it until it opens again. A-Best repairs plaster walls and ceilings the way they need to be repaired: loose plaster reattached, cracks opened up and reinforced, holes built back to the surrounding thickness, and the whole area skim coated to blend into the original wall.

Skim coating, setting-type compounds and feathering a repair into a large flat surface are what drywall finishers do every day. That is most of what a good plaster repair is.

Where San Antonio's plaster walls are

Most homes built before about the 1950s have plaster rather than drywall. In San Antonio that means much of Alamo Heights, Olmos Park, Terrell Hills, Monte Vista, Tobin Hill, King William and the older streets inside Loop 410. Older lath and plaster walls are usually two or three coats of plaster troweled over wood lath. Some mid-century houses have a thinner coat over gypsum lath board. Both can be repaired, and both behave differently from drywall.

Many of these older houses also sit on pier-and-beam foundations rather than a slab. They move a little with the seasons and with the clay soil under them, and plaster is rigid, so the same cracks over doors and windows open and close year after year. If a crack keeps widening, have the foundation looked at before the wall is repaired; see foundation cracks in walls.

Plaster vs drywall: how they differ

	Plaster	Drywall
How it is built	Two or three coats troweled on over wood lath or gypsum lath board	Factory-made gypsum sheets screwed to the studs, seams taped and floated
Thickness	Usually about three-quarters of an inch or more	Usually half an inch in homes
Feel	Hard, cold, sounds solid when knocked	Softer; a thumbtack pushes in
In San Antonio	Most homes built before about the 1950s	Most homes built since
Fixing a crack	Reattach loose plaster, tape in setting compound, skim coat	Re-tape the seam or patch the board
Hanging things	Drill a pilot hole; heavy items into studs or plaster-rated anchors	Standard drywall anchors work

What we repair

• Cracks: long wall cracks, ceiling cracks and cracks off door and window corners
• Loose or bulging plaster: lath and plaster reattached instead of torn out
• Holes: from rewiring, plumbing, old fixtures and removed built-ins
• Water damage: stained, soft or crumbling plaster cut back and rebuilt
• Plaster ceilings: sagging or cracked ceilings stabilized and refinished
• Finish match: smooth, sand-finish or textured, then primed and painted

How a plaster repair holds

The most common mistake is patching over plaster that is no longer attached. It feels solid enough to fill, then cracks again within a season. A lasting repair starts by pressing on the wall around the damage. Plaster that has let go of the lath gets pulled back and fastened with plaster washers or adhesive. Anything crumbling is cut back to sound edges.

Cracks are opened slightly and bridged with tape or mesh in setting-type compound, which bonds to plaster and shrinks far less than premixed patching compound. Holes are built back up in layers to the thickness of the wall around them. Then the area is skim coated wide enough that the edge of the repair cannot be seen in side light, and the surface is finished to match: smooth, sand finish or textured.

That repair-first approach is the same one the National Park Service lays out in its guide to repairing historic plaster walls and ceilings: keep the plaster that is sound, reattach what has let go, and patch with compatible materials. A wall that is wavy or uneven but still attached is usually skim coated flat rather than torn out.

Plaster ceiling repair

Plaster ceilings fail differently from walls. A plaster ceiling is held up by its keys, the ridges of plaster that squeezed through the gaps in the lath when it was first applied. Decades of movement, leaks and footsteps on the floor above break those keys, and the ceiling starts to sag or bulge even when the surface still looks whole. A sagging plaster ceiling is heavy and can come down in pieces, so keep people out from under it.

Most sagging lath and plaster ceilings can be saved. The plaster is pressed back up against the lath and fastened with plaster washers and screws, the cracks are taped, and the whole ceiling is skim coated so the repair doesn't show. Where a ceiling is too far gone, it can be covered with new drywall screwed through to the joists, or taken down and replaced.

Repair, cover or replace?

• Repair when the plaster is mostly attached. It is the least disruptive option and keeps the original walls, trim and door casings in place.
• Cover with thin drywall when the surface is sound but covered in old cracks. A quarter-inch board over the plaster gives a new surface, but it changes how the trim and outlets sit, so it is a bigger job than it sounds.
• Replace with drywall when large areas are loose or water damaged, or the walls are being opened for major rewiring or plumbing anyway.

We will tell you which one your walls actually need after looking at them, not before.

Water-damaged plaster dries slowly

After a leak, thick plaster can stay wet inside long after the surface feels dry, and paint or patching over damp plaster traps the moisture in the wall. Before it is repaired it should be checked with a moisture meter and given time to dry, and anything soft or crumbling is cut back to sound material. The EPA's guide to mold and moisture explains why drying fast matters. See also wet drywall: dry it or replace it.

What plaster repair costs

Plaster is priced after seeing it, because the same crack can be a small patch or the first sign of a ceiling that has let go. What moves the price:

• Loose or just cracked: reattaching plaster takes longer than filling a crack in plaster that is still tight.
• Wall or ceiling: ceilings take more time and more protection for the room below.
• Size: one crack, one wall, or several rooms done in the same visit.
• Finish: smooth, sand finish or texture to match, and whether the whole wall is repainted so the repair does not show.
• Age of the house: lead-safe work practices in a home built before 1978.

Text a photo of the wall to 210-617-8597 for a free written estimate.

Before any work in an older home

Houses built before 1978 can have lead-based paint on the plaster. Cutting or sanding it releases dust, so ask about lead-safe work practices before work starts. The EPA's Renovation, Repair and Painting rule covers this kind of work in older homes.

Cracks that keep coming back can also be a sign the house is still moving. See our guide to foundation cracks in walls, and if the crack runs along the ceiling line, why ceilings crack where they meet the wall.