Effectiveness of radon mitigation in a crawl space using spray foam insulation
Hello, all. My wife and I are having an ICF home built in the Colorado mountains (climate zone 7B). The house will soon be dried-in and has a crawl space with a floor of several inches of small stones. We plan to use the crawlspace for storage. A chaseway is being constructed from the crawl space to the roof of the house in case, after radon measurements are eventually taken by a radon mitigation professional, a sub-membrane depressurization system is called for.
As an alternative to the sub-membrane depressurization system, our contractor indicates that several of his clients have sealed their crawlspaces to prevent radon from gaining entry. They used insulation spray foam (he referenced NCFI InsulStar) to seal the crawl space floor.
Theoretically, I can see how this might work for us – – – sealing out the radon and providing a hard surface that would allow us to use the space for storage. However, I cannot find anything on-line that indicates the sole use of insulation spray foam in a crawl space is an acceptable way to mitigate radon.
There are a couple of Canadian companies that promote using spray foam to mitigate radon . . .
However, other than these sales claims, I cannot find information from an authoritative source (such as USEPA or a scientific study) that documents the long-term effectiveness of using spray foam as a stand-alone means to mitigate radon.
Any experiences, references or ideas on using insulation spray foam to seal out radon from a crawl space floor would be greatly appreciated. Thanks!