Radon, Vents, and Air Leakage
I have a home built by Richmond homes in 1995 in Superior Colorado. The basement floor is not concrete (soil issues), it’s dirt with a plastic covering and a few feet above that is a wooden basement floor. When we purchased the home 14 years ago the radon test came in around 4pCi/L so the original owner put in an active fan radon system for us before we moved in.
I have always wondered about two vents that run from the rim joist down below the basement wood floor. My guess is those two vents provide passive radon mitigation. It’s just a guess since radon gas is heavier than air and might not travel up the vent to outside.
Now that we have an active radon system can I block off those two vents to improve my blower door score (5.9 ACH before I started air sealing)?
I have an Airthings radon monitor and this time of year it is averaging 1.6pCi/L. If I close off those vents I will keep a close eye on the radon levels this coming winter.
I called Richmond homes and left a message weeks ago but they have not returned my call.
Am I right, are those two vents for passive radon mitigation?
(for those wondering, I have 2″ foam board behind that fiberglass at the rim joist.)
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