auradeus

Thank you all. I am not opposed to installing a radon mitigation system, if conservative measures do not work, that's exactly what I will do. But I feel given the relatively low radon exposure and the fact sealing the penetration will take an hour tops of my time, why not try it. Jim, you mentioned heavy rains have an even stronger effect on radon levels. Thank you for sharing this, I did not realize this. Up until this summer, the back yard was pitched toward the house and rainwater from the downspouts would flow right up against the house. I have solved this by regrading and installing dry wells into which the downspouts are directlly routed. Perhaps this will further alleviate radon levels. Thanks again all.

Looking for some advice on a minor radon issue I'm facing. I've tested radon several times over the past two years, including two three-month tests. Radon levels are generally below 4 pCi/l, but one test did spike to 5.5 pCi/l. Radon is only at higher levels in the basement, which is very airtight (new construction, built in 1997). Related to the 5.5 pCi/l test (a 3-month test), where I live near Boston received record winter snow during the test. It is likely the pressure of the snow increased flow of radon into the basement. Looking to try conservative radon mitigation techniques before considering installing a sub-slab suction radon mitigation system, given my levels are borderline. There is a relatively large penetration in the basement slab for the drain to the city sewer. I inserted a picture below. The penetration is about 2' X 2', a little smaller. This is a prime area for radon to enter the basement in high volumes. I'm considering sealing up this area with hydraulic cement, perhaps putting a foam or rubber sleeve around the sewer pipe to alleviate pressure upon expansion of the cement. I have not been able to find guidance whether this is acceptable under building code, but this was one option a local radon mitigation contractor suggested. He also suggested sealing with 6mm plastic using strapping and wire (couldn't really follow what he was recommending, we only spoke on the phone). I realize that this is not a true fix for radon, and that radon will seep through any microscopic crack in the slab. I'm simply trying to slow the flow of radon into the home such that natural ventilation (i.e. opening basement windows, there are many) on occasion will keep levels below 4 pCi/l. Any suggestions or advice is very welcome. Thank you in advance. Click to Enlarge 50.13 KB