Radon Mitigation in Florissant, MO

A radon mitigation system in Florissant, 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 Florissant system around the foundation in front of it.

Does a Florissant home need radon mitigation?

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

Florissant in north St. Louis County was built out mostly between the 1950s and 1970s, so its ranch and split-level homes sit on block or poured basements that are now 50 to 70 years old, with cracks and floor drains that radon uses to enter. If the home has not been tested yet, start with radon testing in Florissant.

Which radon mitigation system fits a Florissant home?

The system follows the foundation:

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

• 1950s and 1960s ranch homes with block basements throughout the city
• Split-level homes from the 1960s and 1970s, where the lower level is often a family room or bedroom
• Homes in Old Town Florissant with older foundations and cellars
• Homes with sump pits or floor drains, which are common radon entry points in north county

How is a radon mitigation system installed in Florissant?

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 Florissant 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 Florissant, MO?

Foundation type, suction points and fan size set the price of a Florissant 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 Florissant 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.

Florissant neighborhoods and nearby communities

Air Sense Environmental works across Florissant, MO, including Old Town Florissant, the New Halls Ferry Road corridor and the neighborhoods toward Spanish Lake, in ZIP codes 63031, 63033 and 63034. Nearby communities with their own service pages:

• Radon mitigation and testing in Hazelwood, MO
• Radon mitigation and testing in St. Louis, MO
• Radon mitigation and testing in Maryland Heights, MO
• Radon mitigation and testing in St. Charles, MO
• All Air Sense Environmental service areas