Radon Testing & Mitigation in Ballwin, MO

In Ballwin, MO, Air Sense Environmental tests homes for radon, installs radon mitigation systems, tests indoor air quality and encapsulates crawl spaces. Every radon job in St. Louis County is measured against the EPA action level of 4.0 pCi/L, and the team is NRPP-certified and IEMA-licensed (#RNM20232346).

Is radon a problem in Ballwin, MO?

Yes. St. Louis County is in EPA Radon Zone 2, where the predicted average indoor radon level is 2 to 4 pCi/L, and individual Ballwin homes routinely test well above the 4.0 pCi/L action level. Missouri’s Department of Health and Senior Services reports that roughly one in three homes tested through its statewide program between 2003 and 2023 came back at or above 4.0 pCi/L. Ballwin sits on the rolling upland of west St. Louis County, where clay-heavy soils over limestone bedrock hold radon in the ground until a house draws it in.

A Ballwin neighbor’s reading is a signal, not an answer. The soil under one lot, the cracks in one slab and the way one sump pit was sealed decide the number, which is why two similar homes a few doors apart can land on opposite sides of the action level.

Radon testing in Ballwin, MO

A Ballwin radon test runs 48 hours under closed-house conditions on a calibrated continuous monitor, and the report shows the hourly data as well as the average. Radon testing in Ballwin covers how the test works, and the radon testing cost guide holds current pricing.

Radon mitigation in Ballwin, MO

When a Ballwin home tests at or above 4.0 pCi/L, the same team designs and installs the radon mitigation system, usually in a single day, and retests to confirm the home is below the action level. See radon mitigation in Ballwin for the process, documented results and warranty.

Indoor air quality testing in Ballwin, MO

An indoor air quality assessment for a Ballwin home logs particulate matter, chemical vapors, CO2, CO and humidity at one-minute intervals for 48 hours or more, so the fix is based on data. Details are on indoor air quality in Ballwin.

Crawl space encapsulation in Ballwin, MO

For Ballwin homes with a crawl space, encapsulation lays a sealed vapor barrier over the soil and walls and adds humidity control, keeping damp air and soil gas out of the rooms above. Read more on the St. Louis crawl space encapsulation page.

Which Ballwin homes does Air Sense Environmental work on?

The Ballwin homes the team sees most often:

• Split-level and two-story homes from the 1960s to 1990s subdivisions off Manchester Road, most with full basements
• Walkout-basement homes on the hillier lots toward Castlewood State Park
• Ranch homes with a partial basement and a crawl space under an addition
• Newer infill homes on poured foundations, which are not exempt: sub-slab gravel moves radon efficiently

What should Ballwin homeowners expect?

1. Test first. A 48-hour continuous monitor test gives the number everything else depends on.
2. Read the report together. You get the hourly data and a plain explanation of what it means for the house.
3. Design the fix. If the reading is at or above 4.0 pCi/L, the system is designed around your foundation during a free in-home estimate.
4. Install and verify. Most systems go in within a single day, and a post-mitigation test confirms the result.

Ballwin neighborhoods and nearby communities

Air Sense Environmental works across Ballwin, MO, including Vlasis Park, the Manchester Road corridor and the neighborhoods above Castlewood State Park, in ZIP codes 63011 and 63021. Nearby communities with their own service pages:

• Radon testing and mitigation in Chesterfield, MO
• Radon testing and mitigation in Kirkwood, MO
• Radon testing and mitigation in Eureka, MO
• Radon testing and mitigation in Valley Park, MO
• All Air Sense Environmental service areas

From Our Work