Radon Mitigation in Chesterfield, MO

Radon mitigation in Chesterfield, MO fixes a home that tested at or above the EPA action level of 4.0 pCi/L. Air Sense Environmental installs sub-slab and sub-membrane depressurization systems across St. Louis County, routes the fan outside the living space, and retests to confirm the number came down.

Does a Chesterfield home need radon mitigation?

Mitigation follows measurement. If a Chesterfield home tests at or above 4.0 pCi/L the EPA recommends a system, and readings between 2 and 4 pCi/L are worth discussing. St. Louis County is in EPA Radon Zone 2, where the predicted average indoor radon level is 2 to 4 pCi/L, and individual Chesterfield 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.

Chesterfield splits into two very different foundations: the Chesterfield Valley, the Missouri River floodplain once called Gumbo Flats, with deep silty soil, and the hills above it where 1970s to 1990s subdivisions sit on clay over bedrock. If the home has not been tested yet, start with radon testing in Chesterfield.

Which radon mitigation system fits a Chesterfield home?

The system follows the foundation:

• Basement slab: sub-slab depressurization, the most common system in Chesterfield
• Crawl space: sub-membrane depressurization under a sealed vapor barrier
• Sump pit: a sealed sump lid tied into the system, covered in the sump pump radon mitigation guide
• Slab-on-grade: a suction point routed through a garage, closet or exterior wall
• Mixed foundations: multiple suction points balanced on one fan

The Chesterfield homes Air Sense Environmental mitigates most often:

• Two-story and walkout-basement homes in the subdivisions off Clarkson Road and Olive Boulevard
• Homes in the older parts of Chesterfield built before the city incorporated in 1988
• Slab-on-grade and newer homes in and around the Chesterfield Valley
• Homes with finished basements used as bedrooms or offices, where the lowest occupied level is where people spend their time

How is a radon mitigation system installed in Chesterfield?

1. Assessment and diagnostics. The foundation, sump, cracks and pipe route are checked during a free in-home estimate.
2. Suction point. A core hole through the slab, or a sealed membrane in a crawl space, gives the fan something to pull from.
3. Pipe and fan. PVC pipe runs to a fan mounted outside the living space, in the attic, garage or on an exterior wall, and vents above the roofline.
4. Sealing. Cracks, the sump lid and other openings are sealed so the fan can hold suction.
5. Manometer and verification. A U-tube manometer shows the system is running, and a post-mitigation test proves the result.

Most Chesterfield installations are completed in a single day. The full walk-through is on the radon mitigation system installation page.

How much does radon mitigation cost in Chesterfield, MO?

Air Sense Environmental quotes each Chesterfield job after seeing the foundation, because suction points and fan size drive the cost. For current ranges by system type, see the St. Louis radon mitigation cost guide.

How do you know the radon mitigation system worked?

A post-mitigation radon test is the only proof. Air Sense Environmental includes it, designs Chesterfield systems to a target well below the 4.0 pCi/L action level, and recommends retesting every two years. When a fan eventually wears out, radon fan replacement restores the system.

Chesterfield neighborhoods and nearby communities

Air Sense Environmental works across Chesterfield, MO, including Chesterfield Valley, the Clarkson Road corridor and the neighborhoods above Faust Park, in ZIP codes 63005 and 63017. Nearby communities with their own service pages:

• Radon mitigation and testing in Ballwin, MO
• Radon mitigation and testing in Maryland Heights, MO
• Radon mitigation and testing in Wildwood, MO
• Radon mitigation and testing in Creve Coeur, MO
• All Air Sense Environmental service areas

From Our Work