Answer: Normally a short-term radon test is best done in the coldest months - December or January. A reading over 4 usually dictates a mitigation. But a reading of 4 in January means your AVERAGE reading throughout the year is more like 1.

Radon is a hotly debated subject. I've heard health physicists (the experts on the subject) say that radon risk is severely overstated. But the way I look at it is when I go to sell my house I'll probably have to mitigate the radon. Why not do it now and be on the safe side, probably save a little money (mitigation will probably cost more by the time I sell) and be able to finish my basement, which could be torn up a bit by subsequent mitigation.

Typically for mitigation (remediation) a system called "sub-slab suction" is used. At it's most basic level (which would most likely be enough for your low reading) it consists of a 4" hole cut into your basement floor. A plastic pipe is fitted into the hole and routed the the garage, attic, or outside, with a suction fan en route. Negative pressure is created beneath the slab. This prevents radon from seeping in. Oh, any cracks in the basement concrete are sealed using URETHANE caulk. This caulk is available in regular and flowable varieties.

I've read all the literature, talked to about 6 contractors, and done mitigation on my own house. Our level was 30 pc/l in winter. Now (in spring) it came it at 0.7 pc/l.

Question: A contractor we spoke with over the phone suggested that the dry well in the basement could be the cause of the problem and said one solution would be to cap it. We might give that a try--sounds cheapest!

Answer: Yes I would agree this is the first thing to do. Follow up with a short-term test in January.

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