Q&A Forums Registered User
Posted: 11/15/2012 10:20 PM EST
RE: What happens when foam gets wet?
There are two types of foam. Closed Cell and open cell. Closed cell is the one that pertains to hurricane resistance.
Closed cell foam is an adhesive and can strengthen the wood structure of a home by 250-300% when sprayed on the under deck of the roof and exterior walls. It has the highest R value of any home insulation per inch, it is a water plain so water will run off of it and not be soaked up by it like other insulation. FEMA requires it when rebuilding in hurricane prone zones.
It is an air barrier preventing cold wind/moisture blowing in through cracks or openings in the structure for plumbing/electrical systems.
Since it is water resistant it can be used below grade in basements, areas expected to get wet, hard to reach or seal areas. If it is used outside it requires a UV barrier. It can be effective in as little as 1" or 1 1/2" thickness.