Radon mitigation in new construction is now routine when testing finds that concentrations of this odorless, cancer-causing gas exceed government-recommended levels. Writing from southeastern Wisconsin, Andrew S. has a slightly different problem: How to control radon levels when you live in a leaky log home built in the 19th century.
“Our radon issue is being worked on via traditional methods with mixed success,” he writes in a Q&A post at GreenBuildingAdvisor. “The radon issue improves dramatically when windows are open — I assume this is dilution and perhaps also pressure equalization?”
That may be fine in warmer weather, but leaving windows open during the winter in Climate Zone 6 to keep the concentration of radon under control doesn’t seem like much of a solution.
Andrew wonders whether other forms of ventilation might help. He weighs two possible options:
Andrew knew about the radon problem when he bought the house, but he was assured by a well-recommended radon specialist in the area that controlling it would not be a problem. When the sale went through, that expert came to look at the house — and never came back. Other contractors have looked but never followed through with a plan. Although Andrew has found a contractor who’s willing to work on the problem, he still has his doubts that a traditional approach will work.
So what will?
That’s the topic for this Q&A Spotlight.
What’s been tried so far
There are essentially five “basement systems” in the house, Andrew explains, including two basement foundations, two dirt crawl spaces, and a slab-on-grade room. Here’s what they’ve done:
The U.S. Environmental Protection Agency sets the “action level” for radon at 4.0 picoCuries per liter (pCi/L), and when the door to the room built on a…