Design/build strategies that reduce the threat of moisture problems
Spray foam insulation can significantly contribute beyond the expected benefits of energy efficiency, comfort and enhanced indoor air quality. Moisture is one of the most damaging issues in any building, and proper moisture management can help lessen the risk of jeopardized building performance, health, safety and durability.
Most moisture-related problems in commercial buildings are caused by four key mechanisms of water movement:
- bulk water transfer
- wicking/capillary action
- air leakage
- vapor diffusion
Closed-cell and open-cell spray foam insulation contribute to moisture management to help maintain optimal building performance in several ways. Spray foam’s insulating properties help keep surface temperatures regulated, thereby minimizing the potential for condensation. Spray foam’s air barrier properties can help minimize the movement of moisture-laden air within the building envelope and its associated moisture problems.
Moisture management with closed-cell spray foam insulation
- Closed-cell spray foam insulation can act as a Class II vapor retarder, an important feature particularly in Climate Zones 5-8 and Marine 4
- Closed-cell spray foam insulation does not absorb water, even when submerged
- Ideal for below-grade applications, making it an advantage in flood zones (FEMA-approved material)
- Ability to create a continuous air barrier without time-consuming, labor-intensive and costly detailing
- Helps prevent excessive heat loss/gain through framing for fewer cold spots to attract condensation
Moisture management with open-cell spray foam insulation
- Open-cell’s vapor permeability enhances an assembly’s ability to dry out via diffusion should it become wet
- Open-cell spray foam may absorb moisture if subjected to hydrostatic pressure but will allow moisture to drain through
- Open-cell spray foam will not wick water or contribute to capillary action
- When applied to the interior cavity, open-cell can also be supplemented with closed-cell spray foam to create a continuous insulation layer on the exterior. This can help limit moisture ingress from the exterior and help control cavity temperatures to avoid condensation
