Radon Mitigation in St. Charles, MO

A radon mitigation system in St. Charles, MO is a sealed pipe and a continuously running fan that pull radon from under the house and release it outdoors, bringing the home below the EPA action level of 4.0 pCi/L. Air Sense Environmental, IEMA-licensed (#RNM20232346) and NRPP-certified, designs each St. Charles system around the foundation in front of it.

Does a St. Charles home need radon mitigation?

The trigger is the test result: at or above 4.0 pCi/L the EPA recommends fixing a St. Charles home, and between 2 and 4 pCi/L it suggests considering it. St. Charles County is in EPA Radon Zone 2, where the predicted average indoor radon level is 2 to 4 pCi/L, and individual St. Charles 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.

St. Charles combines historic Main Street and Frenchtown, with 1800s brick homes on stone foundations, and the tri-level and split-level subdivisions built from the 1960s to the 1980s across the rest of the city. If the home has not been tested yet, start with radon testing in St. Charles.

Which radon mitigation system fits a St. Charles home?

The system follows the foundation:

• Basement slab: sub-slab depressurization, the most common system in St. Charles
• 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 St. Charles homes Air Sense Environmental mitigates most often:

• Historic homes near Main Street and Frenchtown with stone foundations and cellars
• Tri-level and split-level homes from the 1960s to 1980s, where the lower level is usually a living space
• Ranch homes with basements in the neighborhoods off Zumbehl Road and Elm Street
• Newer subdivisions on poured basements toward New Town and the Highway 94 corridor

How is a radon mitigation system installed in St. Charles?

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 St. Charles 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 St. Charles, MO?

Foundation type, suction points and fan size set the price of a St. Charles system, which is why quotes follow a free in-home assessment. The St. Louis radon mitigation cost guide lists the current ranges by system type.

How do you know the radon mitigation system worked?

A post-mitigation radon test is the only proof. Air Sense Environmental includes it, designs St. Charles 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.

St. Charles neighborhoods and nearby communities

Air Sense Environmental works across St. Charles, MO, including historic Main Street, Frenchtown and the neighborhoods along the Highway 94 corridor, in ZIP codes 63301, 63303 and 63304. Nearby communities with their own service pages:

• Radon mitigation and testing in St. Peters, MO
• Radon mitigation and testing in O’Fallon, MO
• Radon mitigation and testing in Maryland Heights, MO
• Radon mitigation and testing in Florissant, MO
• All Air Sense Environmental service areas