Plaster walls take longer to dry than drywall because plaster is thicker and denser, and it sits on wood lath strips that soak up water and hold it. The surface can look and feel dry while the plaster core and the lath behind it are still wet, which is how mold and peeling paint show up weeks later. Plaster needs moisture readings, not a touch test. Wet plaster walls? Call (413) 603-1274.
The differences
| Plaster and lath | Drywall | |
|---|---|---|
| Thickness | Often 3/4 inch or more | Usually 1/2 inch |
| Behind it | Wood lath strips that absorb water | Studs and a hollow cavity |
| When wet | Stays firm longer, dries slowly | Softens and sags fast |
| Drying in place | Often possible if still firm | Possible only if caught quickly |
Why it matters in Chicopee
About a quarter of Chicopee homes were built before 1940, when plaster and lath were standard, and many later homes still have plaster in the original rooms. In two- and three-deckers, a burst pipe in one wall often soaks plaster on several floors. Firm plaster is worth drying, not tearing out, but only if it is really dry before it is painted and closed up.
How we dry plaster
- Readings from the surface and into the wall to see how deep the water went
- Dehumidifiers to pull moisture out of the room air
- Small openings or drilled holes to move dry air into the cavity behind the lath
- Patience: often several days longer than drywall
- Removal only where plaster has gone soft or come loose from the lath
See drywall and plaster water damage repair and structural drying.
Signs plaster has failed
- The wall sounds hollow when you tap it, where it used to sound solid
- A bulge or wave in the surface
- Cracks that open up as it dries
- Plaster that crumbles or feels soft when pressed
- The ceiling sags away from the joists
Hollow sounds mean the plaster has come loose from the wood lath behind it, called losing its keys. Small loose areas can often be reattached with plaster washers and adhesive once dry. Large loose areas, especially on ceilings, should come down.
Patching after drying
Old plaster can be repaired with new plaster, or with drywall shimmed to the same thickness and skimmed to blend in. In historic homes, matching the wall's surface matters as much as the patch itself. Paint only after the readings show the wall is dry, or the new paint will peel and the stain will bleed through.
Don't rush the paint
Plaster that looks dry may still hold water deep inside. Painting too soon traps it, and the paint bubbles, peels or stains. Wait until readings match a dry wall of the same kind. Then prime with a stain-blocking primer before painting. Rushing this step is the most common reason plaster repairs fail. Patience saves the wall.
Questions
Can wet plaster be saved?
Often, if it is still hard and attached. Soft, crumbling or bulging plaster has to come down.
Is old plaster safe to cut?
Paint on walls in homes built before 1978 may contain lead, so work should follow lead-safe practices.
Wet plaster walls? Call now
Call (413) 603-1274 now. Locally owned in Chicopee. See how to tell if water is still in your walls.