SYSTEMS

Basement, Crawl-Space and Slab Radon Systems

Every home is different. The right radon mitigation system depends on your foundation type, home layout, and where radon is entering.

Clean basement with a white radon mitigation pipe and manometer

A basement radon mitigation system with the pipe, fan, and manometer visible.

BY FOUNDATION

How systems differ by foundation type

A qualified professional will recommend the right approach for your home.

Basement foundations

For homes with full or partial basements, the most common approach is sub-slab depressurization. A suction point is created by drilling through the concrete floor slab, and a pipe is routed from that point through the home or along the exterior to a fan, then vented above the roofline.

The suction point is typically located in the basement floor

The sump pit may be sealed and used as part of the system

Cracks in the floor and walls are sealed to improve efficiency

The pipe can be routed through interior closets or along the exterior

Crawl-space foundations

For homes with crawl spaces, a vapor barrier is installed over the exposed soil and sealed to the foundation walls. A fan draws radon from beneath the barrier and vents it outside, similar to sub-slab depressurization.

A durable vapor barrier is laid over the crawl-space floor

The barrier is sealed to the foundation walls and piers

A fan creates suction beneath the barrier

Crawl-space vents may be sealed depending on the design

Slab-on-grade foundations

For homes built on a concrete slab without a basement, a suction point is installed through the slab and the pipe is routed to the exterior. Slab homes often have the simplest installation path.

A suction point is drilled through the concrete slab

The pipe is routed along the exterior wall to the fan

Cracks and joints in the slab are sealed

The vent exits above the roofline

PIPE ROUTING

Interior vs. exterior pipe routing

The pipe that carries radon from beneath your home to above the roofline can be routed through the interior or along the exterior.

Interior routing

The pipe runs through closets, utility chases, or finished spaces inside the home. This keeps the exterior clean but may require more labor if the path is complex.

Exterior routing

The pipe exits the foundation and runs up the exterior wall to the roofline. This is often simpler and less expensive, though the pipe is visible from outside.

Columbia home with exterior radon mitigation pipe running up the side wall

MONITORING

How to know your system is working

Every mitigation system includes a manometer—a simple U-tube pressure gauge mounted on the pipe.

The manometer shows the pressure difference created by the fan. When the system is working, the liquid levels in the U-tube are unequal, indicating the fan is pulling a vacuum beneath your floor. If the levels are equal, the fan may not be running and you should check the power or contact a professional.

Missouri DHSS recommends retesting every two years to confirm your radon level remains low, even with a mitigation system in place. A post-mitigation test should be conducted 24 hours to 30 days after installation.

Having a problem with an existing system?

READY TO ACT?

Request a system assessment

A local radon professional can evaluate your foundation and recommend the right system for your home.

EPA Mitigation Guidance