Can Spray Foam Insulation Handle Moisture?

Closed-cell spray foam has a dense structure that acts as a vapor barrier and resists liquid water. It is often used in areas where moisture is a significant concern, such as crawlspaces or slab foundations. In contrast, open-cell foam is less dense and more permeable. It can absorb and hold moisture from the air, which may reduce its insulating properties over time in a humid environment. Understanding this difference is key to knowing how your insulation reacts to water.

You might notice a musty smell or see mold on baseboards or ceilings. Warping or staining of your drywall can indicate moisture behind it. In a hot, humid climate, these signs are more common due to the high level of moisture in the air. These clues often mean water is present in a concealed cavity, requiring investigation.

• A persistent musty odor in a room.
• Visible mold growth on surfaces near insulated areas.
• Warping or staining on drywall or wood trim.
• Unexplained increases in indoor humidity levels.
• Soft spots or crumbling in adjacent building materials.
• Condensation forming on interior walls or windows.

If foam insulation is wet, the pros will likely need to remove the affected sections. This allows for proper drying of the structural wood and sheathing underneath. After the area is completely dry, new insulation can be installed. The process often includes addressing the original leak source, such as a broken pipe or roof issue, to prevent a recurrence. They may also treat the area for mold if any growth is discovered on the building materials.