Building a new home to keep radon out

Can a new home be built to keep radon out?

Yes. PA DEP says radon-resistant construction can be effective at preventing radon from getting in, and that these features usually keep radon levels in new homes below 2 pCi/L. It's almost always cheaper to build them in than to fix an existing house later.

What is radon-resistant construction?

DEP describes it as simple, inexpensive techniques put in while the house is built. Together they make a passive radon system: the pipework is there, but it relies on natural air movement rather than a fan.

For the details, DEP points builders to EPA's guide, Building Radon Out: A Step-by-Step Guide on How to Build Radon-Resistant Homes.

Does a passive system always work?

Not always. DEP says passive subslab suction is generally not as effective at reducing high radon levels as a system with a fan. It typically cuts radon by 30 to 70 percent, against 55 to 99 percent with a fan.

That's why the test after you move in matters. If it's still 4 pCi/L or more, DEP says to have a certified mitigator add a vent fan to the passive system. DEP puts that at about $300.

What should you ask your builder?

DEP suggests asking whether they use radon-resistant construction features. Your builder can follow EPA's Building Radon Out guide, or work with a qualified contractor to design and install the system.

Once a new home is occupied, DEP says every professionally installed radon system must be put in by a Pennsylvania-certified radon mitigator, following DEP's Pennsylvania Radon Mitigation Standards.

What about buying a new home?

If you're buying or renting a new home, DEP says to ask the owner or builder whether it has radon-resistant features, and to test it after you move in either way. See radon in a Pennsylvania home sale.