Monday, April 14th, 2014
The EPA recommends employing radon mitigation techniques to reduce the radon measurement in your home to less than 2 pCi per L.
Suppose you have already tested your home for radon levels and the result is 4 or more picocuries (a measurement of radioactivity) per liter of air. The EPA recommends employing radon mitigation techniques to reduce that measurement to less than 2 pCi per L. Before employing anyone for radon mitigation services, be sure they are certified mitigation specialists. It may also help to learn more about construction features that contribute to your radon test results. Both the EPA and the Pennsylvania Department of Environmental Protection have pamphlets that describe effective radon mitigation techniques.
Any building can contain radon regardless of construction material or foundation, and may be in need of radon mitigation.
There are several basic kinds of foundations: a basement, a concrete slab on grade, a crawlspace, or a manufactured home elevated on piers. Aside from an open pier design, the other forms of foundation construction, involving direct contact with soil, can contribute to a higher interior radon measurement. Radon can easily enter a building through cracks and breaks in exterior walls and foundations, where a concrete foundation meets walls or when the soil surrounds a basement. In the case of a crawlspace, radon gas from soil in the crawlspace can easily mix with building air. Concrete itself is porous.
Once radon gas is indoors, ordinary efforts to reduce utility costs by weatherproofing and sealing windows and doors and poor ventilation can keep the radon there.
The "Stack Effect" is when air with radon from around and under a building has a higher pressure than air within the building.
Finally, any multistory building is subject to the “stack effect.” Air with radon from around and under a building has higher pressure than air within the building. And, warm air rises and exits to the outside through the roof. As heated air within the building rises, it actually pulls in outside air through cracks or breaks in the foundation, drawing it upward. For these reasons, radon levels are likely to be higher when doors and windows are kept closed and the interior air is heated, than during periods when windows and doors can be left open for natural cooling and ventilation.
In new construction, it is possible to "Build Radon Out."
Although construction features and energy conservation efforts contribute to higher radon gas levels within buildings, the good news is that it is possible to “build radon out”, reducing radon levels in any building through relatively simple and economical construction techniques and materials. While it is easier and less expensive to add radon-resistant features to new construction, they can also be added to existing structures. Systems may be either active (employing a fan) or passive (no fan).
Radon Mitigation Specialists can help builders and homeowners determine the best radon mitigation methods for each situation.
Radon Mitigation is no place for do-it-yourself remedies, unless you are a certified radon mitigation specialist. To ensure safety, testing should be performed before and after mitigation and buildings should be retested to verify radon levels. In Pennsylvania, the Radon division of the Department of Environmental Protection provides free post-mitigation confirmatory testing if you have installed a fan-powered (active) mitigation system in the last year.