Radon Testing & Mitigation in Florissant, MO

In Florissant, 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 Florissant, 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 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.

A Florissant 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 Florissant, MO

A Florissant 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 Florissant covers how the test works, and the radon testing cost guide holds current pricing.

Radon mitigation in Florissant, MO

When a Florissant 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 Florissant for the process, documented results and warranty.

Indoor air quality testing in Florissant, MO

An indoor air quality assessment for a Florissant 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 the St. Louis indoor air quality testing page.

Crawl space encapsulation in Florissant, MO

For Florissant 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 Florissant homes does Air Sense Environmental work on?

The Florissant homes the team sees 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

What should Florissant 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.

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

From Our Work