Clues that water is still inside a wall include a stain that keeps spreading, bubbling or peeling paint, soft spots, swelling baseboards and a musty smell. But walls can look and feel dry while the inside is wet, so the only reliable test is a moisture meter, compared to a dry wall of the same material elsewhere in the house. Want it checked? Call (413) 603-1274.
Signs to look for
- A stain that grows, darkens or forms rings
- Paint bubbles, blisters or peeling
- Drywall that dents when pressed, or plaster that sounds hollow
- Baseboards swelling or pulling away
- Floors near the wall cupping or lifting
- A musty smell, strongest near the floor
- The room feeling damp or windows fogging
Why surfaces fool you
Paint slows evaporation, so the face of a wall can dry while the core stays wet. Plaster and the wood lath behind it hold water for days. The bottom plate of the wall and the insulation can stay wet for weeks. See why plaster takes longer to dry.
How it is measured
- Take readings on a dry wall of the same material as a reference.
- Take readings across the wet area in a grid, low and high.
- Mark where readings are above the reference.
- Repeat during drying until every point matches the reference.
Ask any drying company for these readings. See leak detection and moisture mapping and structural drying.
How long walls take to dry
| Wall | Typical drying with equipment |
|---|---|
| Drywall over studs, no insulation | 2 to 3 days |
| Drywall with wet insulation removed | 3 to 5 days |
| Plaster on wood lath | Often 4 to 7 days or more |
| Wall over a wet subfloor or sill | Longer, until the wood below is dry |
These are typical ranges, not promises. Readings decide when a wall is done.
What happens if you close it up wet
Painting or covering a wall that is still wet inside traps the moisture. Mold grows on the back of the drywall, nail heads rust and pop, new paint peels, and the musty smell comes back. Repairs done too early often have to be done twice. Waiting a few extra days for readings to match is cheaper than redoing a wall.
Insulated outside walls
Exterior walls with fiberglass insulation are the slowest to dry because the insulation holds water against the studs. If readings stay high, the insulation usually needs to come out.
Infrared cameras
Infrared cameras show temperature differences, and wet areas often appear cooler because water evaporating takes heat with it. They help find where to take readings. They do not measure moisture themselves, so a cool spot on an infrared image still needs a moisture meter to confirm it is wet. Readings, not pictures, decide when a wall is dry. Ask to see both the images and the meter numbers, and keep them with your insurance records.
Questions
Can I buy a cheap moisture meter?
A basic meter helps you compare wet and dry spots. Readings vary by material, so compare to a dry spot of the same material.
Is a musty smell always mold?
It usually means dampness that can lead to mold. See how to check for mold after a leak.
Think it is still wet? Call
Call (413) 603-1274 now. Locally owned in Chicopee.