How we repair a plaster crack

The crack opened slightly and loose material cleared so the patch has something to grip
Hollow-sounding areas pinned back to the lath with plaster washers before filling
Mesh tape and a setting compound suited to plaster, built up in thin coats
Sand-finish or smooth surfaces matched as closely as the wall allows
Primer and paint over the repair, feathered into the wall around it

Plaster walls in a pre-war city

The City’s citywide historic resources survey describes San Gabriel as “primarily developed with detached single-family residences,” mostly “Period Revival, Minimal Traditional, and Ranch” houses from the 1920s to the 1950s, “during which time San Gabriel witnessed the vast majority of its development.” Census data back it up: 2,444 homes predate 1940 and another 2,872 went up in the 1940s.

Those walls have been through earthquakes. The geology section of the City’s Housing Element environmental study puts the Raymond Fault “approximately two miles north of the city” and says “San Gabriel is mainly affected by ground shaking.” The 1987 Whittier Narrows quake closed Mission San Gabriel; the Los Angeles Times reported “large cracks running the length of its south wall.” Plaster in houses nearby carries smaller versions of the same story: diagonal cracks off door corners and ceiling lines that reopen.

Old surfaces can hide old materials. If a wall has a textured coat that’s been there for decades, we keep the sanding to a minimum and talk with you before cutting into it.

When to bring in someone else

A crack wider than a coin’s edge, one that keeps growing, sloping floors, or doors that suddenly bind can point to movement in the structure. Those deserve a look from a structural engineer or foundation specialist first. We can patch and paint afterward.

Photos for a plaster quote

Take a close-up with a coin beside the crack and a wider photo of the whole wall, then text them to (626) 684-3505. Mention whether the crack has come back after an earlier repair.

Plaster repair questions

Do you let me know when you’re heading over?

Yes, a text comes from us before we leave.

What if the plaster is loose over a bigger area than we thought?

We stop and ask. You see the loose section, hear what it adds, and decide before we go further.

Will the patch match my paint?

If you have the leftover paint, we use it. If not, paint is one of those parts that depends on the job, and the quote says which way we’ll go.

What if a repaired crack shows again?

Let us know. When something we did isn’t right, we come back and fix it.

Guides on plaster

Patching old plaster walls without making them worseWhy hard cement patches fail on the soft plaster walls of San Gabriel's older and adobe-style homes, how to tell what you have, and how we repair it.
Getting new paint to stick to old glossy trimHow to tell if trim in an older San Gabriel home has oil-based paint, and how we prep it so new paint sticks instead of peeling.
Hanging art the old way and the new wayHow to use original picture rail molding in an older San Gabriel home, and how we hang gallery walls on plaster without cracking it.

This job sits in our drywall, plaster and paint touch-ups group. For other repairs, see the services overview, or start with the repair guide for San Gabriel’s older homes.

Where the numbers here come from

Plaster crack repair