Home on Concrete Slab: What's the Radon Risk?

Key Points

Should you be concerned about radon if your home is on a concrete slab? Radon is possible in any home, but the amount of risk may vary and it’s easy to test for radon.

Homes built on concrete slabs generally have a lower risk of elevated radon levels than homes with basements.
Radon is a gas that emanates from soil, typically entering homes through the basement level, where it can accumulate and pose higher risks.
Crawlspaces pose less risk for radon because they are usually well-ventilated and open to the outside.
Despite the low risk, the only way to confirm the presence of radon is through testing, which can be done inexpensively with a charcoal absorption canister.

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Transcript

LESLIE: J.C. in North Carolina is on the line with a question about radon. How can we help you?

J.C.: If your home is built on a concrete slab, then are you in danger of radon effect?

TOM: Well, you could potentially be in danger of it but the risk of that would be a far smaller chance of you having an elevated radon level on a concrete slab than if you had a basement. Because radon is a gas that emits from the soil and typically, it gets into the home at the basement level through concrete-block walls and the concrete floor and the gaps around it, builds up in the basement. And it’s typically highest in the basement, then it gets far less on the first floor, second floor and so on.

J.C.: Yes. And I would assume it would be more dangerous with a crawlspace then.

TOM: Actually, I think it’s less dangerous with a crawlspace and here’s why: because crawlspaces are open to the outside all the time, so they’re completely ventilated. So the highest risk would be if A) you were in an area that was prone to radon and B) you had a basement. Then you would definitely want a test.

Now, in North Carolina, there are three different Radon Zone levels: 1, 2 and 3. Very little of the state is in the Radon Zone 1, which is the highest risk. I’d say about 30 percent, maybe 25 percent is in Radon Zone 2 but the rest of the state is all Radon Zone 3, which is the lowest risk.

And in your area, which is Lee County, you’re in Radon Zone 3. So you’re in an area that has a low risk of radon, you’re on a concrete slab. I’d say the likeliness of you having a radon problem is very small but the only way to know is to test, J.C. And you can do that with a charcoal absorption canister very inexpensively.

J.C.: Alright. Well, I do thank you.

TOM: You’re very welcome. Good luck with that project and thanks so much for calling us at 888-MONEY-PIT.