Radon Gas and You
Radon is a cancer-causing radioactive gas that you can’t see, smell or taste. According to the Surgeon General, radon is the second leading cause of lung cancer in the United States. And if you’re a smoker, your chances of contracting lung cancer are even higher if your home has high levels of radon.
Radon gas has been found in homes all over the U.S. EPA recommends that you know what the indoor radon level is in any home you consider buying. Ask the seller for their radon test results. If the home has a radon-reduction system, ask the seller for information they have about the system. If the home has not yet been tested, you should have the housed tested. If you are having a new home built, there are features that can be incorporated into your home during construction to reduce radon levels.
If you are thinking of buying a home, you may decide to accept an earlier test result from the seller, or ask the seller for a new test to be conducted by a qualified radon tester. Before you accept the seller's test, you should determine:
The results of previous testing.
Who conducted the previous test: the homeowner, a radon professional, or some other person.
Where in the home the previous test was taken, especially if you may plan to live in a lower level of the home. For example, the test may have been taken on the first floor. However, if you want to use the basement as living space, test there.
What, if any, structural changes, alterations, or changes in the heating, ventilation, and air conditioning (HVAC) system have been made to the house since the test was done. Such changes may affect radon levels.
If you accept the seller's test, make sure that the test followed the Radon Testing Checklist. If you decide that a new test is needed, discuss it with the seller as soon as possible. If you decide to use a qualified radon tester, check with your state radon office to see if they maintain a list of radon testing companies.
If the home has not yet been tested for radon, make sure that a radon test is done as soon as possible. Consider including provisions in the contract specifying:
Where the test will be located.
Who should conduct the test.
What type of test to do.
When to do the test.
How the seller and the buyer will share the test results and test costs (if necessary).
When radon mitigation measures will be taken and who will pay for them.
Make sure that the test is done in the lowest level of the home suitable for occupancy. This means the lowest level that you are going to use as living space that is finished or does not require renovations prior to use. A state or local radon official or qualified radon tester can help you make some of these decisions. If you decide to finish or renovate an unfinished area of the home in the future, a radon test should be taken before starting the project and after the project is finished. Generally, it is less expensive to install a radon-reduction system before (or during) renovations rather than afterwards.
In a new home, the cost to install passive radon-resistant features during construction is usually between $350 and $500. In some areas, the cost may be as low as $100. A qualified mitigator will charge about $300 to add a vent fan to a passive system, making it an active system and further reducing radon levels. In an existing home, it usually costs between $800 and $2,500 to install a radon mitigation system.
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:
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.