FAQ | Product & Materials

Does Open-Cell Foam absorb moisture or water and cause issues?

The building codes recognizes both open and closed-cell foam as meeting the requirements of a true air-barrier. Since most water vapor is transported with air-flow, an air-barrier will eliminate the vast majority of water vapor movement. However, it is essential that adequate R-value or thermal resistance be incorporated to prevent a dew point and condensation on the surface of the foam. Since open-cell foam is more water permeable than closed-cell, once can incorrectly assume that open-cell foam will result in moisture problems. Open-Cell does not wick moisture out of air, or wick water like sponge. Water will only penetrate through the foam with pressure (i.e. submersion, flooding etc.). In fact, in 96 hour water submersion tests, 0.5lb open-cell foam was found to have a water absorption rate of approximately 25% – no more than typical plywood. Further, 0.8lb foam has a water absorption rate of 2.53%, below that of plywood. Open-cell foam has been successfully used for over two decades with nearly a perfect track record. In general, open-cell foam provides excellent cavity insulation in most conditions and climates.

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