Radon in New Construction
A new home can have elevated radon just like an old one, because radon comes from the ground under the house, not the age of the structure. Radon-resistant new construction features (a passive vent pipe and sealed membrane) reduce risk and make a fan-retrofit cheaper later, but they don't guarantee a result below the EPA's action level.
Why "new" doesn't mean "safe"
Radon originates from uranium decay in soil and bedrock beneath the foundation, a geological fact about the lot, not the building. A brand-new home built on the same York County soil as a 100-year-old farmhouse next door faces the same underlying radon source. Builders in Zone 1 areas increasingly include passive radon-resistant features by code or by choice, but that's a mitigation head start, not immunity.
What radon-resistant new construction actually includes
- A layer of gravel or matting beneath the slab to allow soil gas to move freely to a collection point
- A plastic vapor barrier over that layer
- A vent pipe running from beneath the slab through the house and roof (see our passive vs. active systems guide)
- Sealed foundation cracks and openings at the time of pour, which is far easier than sealing them after the home is finished
Should you test a new home?
Yes, and soon after move-in. If the passive system alone isn't keeping levels below 4 pCi/L, adding a fan to the existing pipe is typically the cheapest mitigation retrofit there is, since the hard part (running the pipe, penetrating the roof) is already done.
Just moved into a new build?
Test first, then reach out if the result is elevated. We'll follow up with next steps.
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