When buying a home in Middle Tennessee, you’ll hear a lot about things like crawlspaces, foundations, and home styles. But one question we often get, especially from informed buyers and agent, is:
“Which types of homes are most likely to have high radon levels?”
Is it homes with basements? Crawlspaces? Slabs?
The answer might surprise you.

Basements and Slabs Typically Show Higher Radon Levels

If you’re assuming that crawlspace homes would naturally have the highest radon concentrations, that’s a common misconception. In reality, homes with basements and slabs are more likely to have elevated radon levels.

Why?

These homes are built in direct contact with the ground, without the air buffer that a vented crawlspace can sometimes provide. When radon gas seeps up from the soil, it has a more direct path into the living space through cracks, gaps, and foundation joints.

But It’s Really About the Soil – Not Just the Foundation

At the end of the day, radon isn’t caused by your home’s design. It’s caused by the soil beneath it. Radon is a naturally occurring radioactive gas that forms when uranium in soil and rock breaks down. It’s colorless, odorless, and can accumulate indoors without any warning signs.

Here in Middle Tennessee, the geology is diverse. Certain areas, especially those with limestone, granite, or shale, may produce higher radon levels regardless of the house style.

That’s why you can’t rely on assumptions like:

“Crawlspace homes are always safer.”
“This part of town doesn’t have radon.”
“New construction means low risk.”

They’re simply not true.

What About Crawlspaces?

While vented crawlspaces can allow some radon to dissipate outdoors (a small “dilution effect”), they aren’t a guarantee of safety. In fact, many crawlspace homes in Middle Tennessee still test above the EPA action level of 4.0 pCi/L.

Factors like:

• Poor ventilation
• High soil gas content
• Foundation cracks
• Improper sealing between the crawlspace and the home interior

…can all allow radon to enter your home, regardless of style or size.

You Have to Test

If there’s one thing we want every Middle Tennessee buyer, seller, and agent to remember, it’s this:

Radon is home-specific, not neighborhood-specific.

You can’t determine safety based on location alone. Two homes, side by side, can have wildly different radon readings based on factors like foundation type, soil makeup, and ventilation.

If your dream home has a finished basement, don’t panic, but don’t skip the radon test either. At Riverside Environmental, we perform EPA-compliant radon tests across the Nashville area, including:

• Single-family homes

• New construction

• Older brick ranches

• Walkout basements and daylight basements

• Homes on slab or crawlspace foundations

We deliver accurate, fast results and offer mitigation consultations when needed.