Types of Radon Mitigation Systems


Types of Radon Mitigation Systems

Types of Radon Mitigation Systems


Radon Mitigation Systems are soil depressurization systems. Radon systems come in several forms and are customized for each unique situation. Learn about the different types of radon mitigation systems and how they can help reduce the radon levels inside a building.

Exterior Installed Radon Mitigation Systems

When a radon system is installed on the exterior of a home or building, the pressurized components of the radon system are located outside while the interior components are under suction. The radon fan is usually installed at knee level opposite of the rim joist. From the fan, the radon vent stack rises above the eave of the home or building. Code states that the vent stack opening must be greater than ten feet from the ground and above the eave. The vent stack opening must also be further than ten feet from a window, door or opening that is not at least two feet below it. The vent stack should rise vertically to exhaust the radon into the atmosphere and prevent re-entrainment. 

Attic Installed Radon Mitigation Systems

Radon Systems installed through the attic space will hide the radon system from view and offer better protection from the freezing and thaw cycle outdoors. In most situations the attic installed radon mitigation system is routed through the garage to the attic space above it. If the garage attic option is unavailable the pipes can, in some cases, be routed through multiple closets or utility chases to rise to the attic space above the home. According to code, the radon fan should always be installed in a well ventilated attic space or the exterior of the home. 

Passive Radon Mitigation Systems

Radon resistant new construction techniques can be used to prevent radon gas entry in new construction homes or buildings. Most radon resistant designs consist of a gas permeable layer of gravel under the concrete slab, a soil gas collection pipe buried within the gravel layer, a suction pipe that extends through an interior wall and the exhaust point above the roof of the home. A correctly installed passive radon mitigation system should also include the sealing of cracks and sumps in the concrete slabs and foundation. The passive radon systems work by creating a vacuum through natural stack effect in the suction pipes and can be converted to active radon systems by installing a radon vent fan. 

Radon Mitigation for Crawl Spaces

Crawl spaces can be major radon entry point locations. Radon gas can enter the livable areas above crawl spaces through the floorboards. To properly prevent this radon entry a crawl space should be sealed using a durable vapor barrier that is sealed air-tight. 

How do radon mitigation systems work?

Radon mitigation systems work through active soil depressurization. In existing homes or buildings with radon problems, active soil depressurization systems (ASD) are installed to block radon gas. ASD systems vent radon gas by creating a vacuum in the soil below the foundation. An active radon vent fan is installed to create a permanent and consistent negative pressure within the system. The negative pressure draws the radon gas to the suction point(s) where it is sucked through the radon system and vented to a safe elevation above the home or building.


Sub-slab depressurization is the means of pulling the radon gas and other soil gas from the soil below a concrete slab. A hole is cored through the concrete slab to reach the soil below it. A radon gas collection chamber is created by removing soil from this area to create greater surface area to suck out the radon gas. Radon suction pipes are installed in the collection chamber and continue to the radon vent fan.

Drain tile depressurization is the means of pulling the radon gas and other soil gas by creating a vacuum within the existing drain tile network of a sump or drainage system. This method allows the radon mitigation system to more easily communicate with the soil surrounding the drain-tile system.


Sub-membrane depressurization is the means of pulling the radon gas and other soil gas from below a vapor barrier. In homes and buildings with exposed dirt or gravel crawl spaces, an air-tight vapor barrier is installed and the radon suction pipes create a vacuum under this membrane.

Block wall depressurization is the means of pulling the radon out by depressurizing the hollow voids within a block wall foundation.


Test your home, school or residential building for radon, our team can test radon levels and install a mitigation system to help protect against health risks associated with this toxic gas.

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