What is Radon?
- Radon is a cancer-causing natural radioactive gas.
- It is an odorless, tasteless and invisible gas produced by the decay of naturally occurring uranium in soil and water.
- Radon is the leading cause of lung cancer among non-smokers and the second leading cause of lung cancer in America.
- It claims about 20,000 lives annually.
- The Surgeon General of the United States issued a Health Advisory in 2005 warning Americans about the need to remedy the problem as soon as possible when the radon level is 4 pCi/L or more. (pico Curies per Liter)
- Although lung cancer can be treated, the survival rate is one of the lowest for those with cancer. From the time of diagnosis, between 11 and 15 percent of those afflicted will live beyond five years.
- Nearly 1 out of every 15 homes in the United States is estimated to have an elevated radon level (4 pCi/L or more).
- For most Americans, their greatest exposure to radon is in their homes; especially in rooms that are below grade (e.g., basements), rooms that are in contact with the ground and those rooms immediately above them.
What Are Radon-Resistant Features?
Radon-resistant techniques (features) may vary for different foundations and site requirements. If you’re having a house built, you can learn about EPA’s Model Standards (and architectural drawings) and explain the techniques to your builder. If your new house was built (or will be built) to be radon-resistant, it will include these basic elements:
The techniques may vary for different foundations and site requirements, but the basic elements are:
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.
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.
Sealing and Caulking
All openings in the concrete foundation floor are sealed to reduce soil gas entry into the home.
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.
￼ Zone 1 counties have a predicted average indoor radon screening level greater than 4 pCi/L (pico curies per liter) (red zones) Highest Potential
￼ Zone 2 counties have a predicted average indoor radon screening level between 2 and 4 pCi/L (orange zones) Moderate Potential
￼ Zone 3 counties have a predicted average indoor radon screening level less than 2 pCi/L (yellow zones) Low Potential