Radon Control Methods

Sub Slab Depressurization System

• Air moves from areas of higher pressure to areas of lower pressure. This moves radon particles in the same direction. By installing a passive sub slab depressurization system, it keeps the underground area of a building at a lower pressure, forcing the air to move out of the building and underground. This helps keep the radon moving away from areas inside the building where the particles could endanger people. The depressurization is accomplished by connecting the slab to outdoor air in order to keep the pressure consistently lower than the inside of the building.

Soil-Gas Retarder

• Polyethylene is known to keep radon particles from moving from one place to another. Because radon can be absorbed into the soil, covering surrounding areas with a continuous membrane of polyethylene keeps radon from moving into the surrounding enclosure. The polyethylene should be 0.15mm thick. While this does not entirely stop the flow of radon particles, it inhibits the ability of the radon from moving and greatly retards the flow.

Foundation Wall Protection

• Hollow block masonry foundation does not provide protection against radon. Adding a continuous platform of solid masonry -- masonry grouted solid -- or a solid concrete beam above the finished ground prevents passage of air from the interior wall to the living space. The elimination of passing air prevents radon from getting into the home or building.

Crawl Space and Ducts

• If duct work passes beneath the slab or foundation, it must be made of seamless material to prevent radon leakage. Another method requires maintaining positive pressure in the duct work at all times. This keeps any leaking of air or radon at bay. Crawl space entries must be thoroughly caulked or filled to stop the passage of air. A sub-membrane depressurization system can be installed for additional protection.