The short answer
Stop the Water Source First
Before you start drying, you must stop the water flowing into the plaster. Find and shut off the supply line for a burst pipe, or place a bucket under a roof leak. If the leak is from an appliance, turn the water valve off behind it. Letting water continue will ruin your drying efforts and cause more structural damage. For a persistent leak, you may need to contact a plumber or roofer to make a permanent repair before drying can be effective.
Assess the Extent of Damage
Check how wet the plaster is. Light dampness might dry on its own with good ventilation. If the plaster feels soft, is bulging, or has turned a darker color, the water has deeply saturated the material. Press on the wall gently; if your finger leaves an indentation, the plaster's integrity is compromised. Also, tap the wall; a hollow sound can indicate the plaster has separated from its lath backing, which is a sign of serious damage that likely needs professional attention.
Begin the Drying Process
Move furniture away from the wet wall and remove any wet items touching it, such as pictures or curtains. Open windows if the outside air is drier than inside, but close them if outdoor humidity is high. Set up oscillating fans to blow air directly across the plaster's surface. Running a dehumidifier in the same room is crucial, as it pulls water vapor from the air, speeding up evaporation from the wall. This combination helps draw moisture out through the plaster's surface.
- Use multiple fans for cross-ventilation.
- Point fans at the wall from a few feet away.
- Empty the dehumidifier's collection bucket regularly.
- Monitor the room's humidity with a meter if possible.
- Keep the area warm to aid evaporation.
- Check for drying progress daily.
When to Remove Wet Plaster
Plaster that is sagging, crumbly, or has developed mold must be removed. You cannot dry it effectively in that state. Carefully cut out the damaged section with a utility knife, wearing a mask and gloves to protect from dust and potential mold spores. This exposes the wall cavity, which also needs drying. The lath or framing behind the plaster must be completely dry before any new material is installed; otherwise, trapped moisture will lead to rot and mold inside the wall.
Knowing When to Call for Help
If the affected area is large, if water came from a contaminated source like a sewer, or if drying isn't working after a few days, contact local water damage pros. They use moisture meters, infrared cameras, and industrial air movers to dry walls properly and prevent hidden mold. They can also assess whether the framing inside the wall is still sound. Policies vary, and your insurer decides what is covered. It is wise to document the damage with photos for your records.
Water damage does not wait
Call (208) 537-2633 any time, day or night, and describe what happened.
Call Now (208) 537-2633Frequently asked questions
How long does it take for plaster to dry?
Drying time depends on thickness, humidity, and airflow. A damp spot may dry in a day or two with fans. Saturated plaster can take over a week. If it's not drying, the wall cavity may be wet, requiring professional equipment.
Can wet plaster be saved?
Sometimes. If the plaster is only surface-damp and still firm, drying can save it. If it's soft, stained, or bulging, the damaged section usually needs removal and replacement to prevent mold and structural issues.
Will drying wet plaster prevent mold?
Rapid, thorough drying is the best way to prevent mold. Mold needs moisture to grow. If you dry the plaster and the space behind it completely within 24 to 48 hours, you significantly reduce the mold risk.