Installing Radon-Resistant Features


How much does it cost to reduce radon in an existing home?

If a home with a vent system is found to have an elevated radon level, a fan can be added at a low cost. The total cost is much lower than adding the entire system after the building is completed. The average cost to install radon-resistant features in an existing home is $800 to $2,500. The average cost to install radon-resistant features in a new home during construction is $350 to $500 (a 128% to 400% saving).

Who should I hire to install radon-resistant features?

Talk to your builder about installing a radon-reduction system during major renovations or new construction. Radon-resistant features can be easily and inexpensively installed with common building practices and materials. Many builders already incorporate some of these steps in the construction of their houses to control moisture or increase energy efficiency, using either their own crews or a radon contractor. To find out about builders in your location use the EPA Directory (link is external).

What are radon-resistant features?


The techniques vary for different foundations and site requirements, but the basic elements are:

A.   Gas Permeable Layer—This layer is placed beneath the slab or flooring system to allow the soil gas to move freely underneath the house. In many cases, the material used is a 4-inch layer of clean gravel.

B.   Plastic Sheeting—Plastic sheeting is placed on top of the gas permeable layer and under the slab to help prevent the soil gas from entering the home. In crawlspaces, the sheeting is placed over the crawlspace floor.

C.   Sealing and Caulking—All openings in the concrete foundation floor are sealed to reduce soil gas entry into the home.

D.   Vent Pipe—A 3- or 4-inch gas-tight or PVC pipe (commonly used for plumbing) runs from the gas permeable layer through the house to the roof to safely vent radon and other soil gases above the house.

E.   Junction Box—An electrical junction box is installed in case an electric venting fan is needed later.

For a checklist of these items click here: RRNC Checklist (link is external) (1 page, 381 KB)

For a detailed technical guide to RRNC click here: See Building Radon Out  (84 pp, 5.5 MB)