Someone went to our radon site and asked:
I’m thinking of mitigating my basement radon of 7.75 pci/l. It’s a parcel slab with a crawl space. Why can’t I just install an exhaust fan in the basement? Instead of PVC piping, drilling into the slab and sucking out the air underneath the membrane in the crawl space, etc. I have a high efficiency furnace with a fresh air inlet that wouldn’t create negative pressure.
Phil’s reply:
You didn’t say where or how you made your radon measurement. If your measurement was 7.75 pCi/L in the basement, and you don’t use the basement as living space, then you might not want to do anything, especially if your basement isn’t very well connected to the rest of the house. Before making any costly decisions, we recommend a long-term measurement in the living area of your house.
http://www.cdphe.state.co.us/hm/rad/radon/radonlists.htm has information about Colorado radon mitigators. If you do decide to mitigate, I suggest you speak with one or two of them before doing anything on your own.
Venting the air from the basement can create even higher radon levels. The increased negative pressure caused by the loss of air from the basement can pull radon in from other entry points. Actively venting the basement will cause a loss of conditioned air increasing the heating and cooling expenses and create potential back-drafting situation. I recommend installing a Sub Slab Depressurization system with an auxiliary suction point depressurizing a crawlspace membrane. The crawlspace membrane should always be sealed air-tight to prevent the effects of losing that conditioned air. I would be glad to answer any radon mitigation questions. http://www.radovent.com