Radon and New Construction
Why should I buy a radon-resistant home?
Radon-resistant techniques work. When installed properly and completely, these simple and inexpensive passive techniques can help to reduce radon levels. In addition, installing them during construction makes it easier to reduce radon levels further if the passive techniques don’t reduce radon levels below 4 pCi/L. Radon-resistant techniques may also help to lower moisture levels and those of other soil gases. Radon-resistant techniques:
- Easy upgrades: Even if built to be radon-resistant, every new home should be tested for radon after occupancy. If you have a test result of 4 pCi/L or more, a vent fan can easily be added to the passive system to make it an active system and further reduce radon levels.
- Cost-effective: Building radon-resistant features into the house during construction is easier and cheaper than fixing a radon problem from scratch later. Let your builder know that radon-resistant features are easy to install using common building materials.
- Money savings: When installed properly and completely, radon-resistant techniques can also make your home more energy-efficient and help you save on your energy costs.
In a new home, the cost to install passive radon-resistant features during construction is usually between $350 to $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 reducing radon levels. It usually costs between $800 to $2,500 to install a radon mitigation system in an existing home.
What are radon-resistant features?
Radon-resistant features may vary for different foundations and site requirements. If you’re having a house built, you can learn about the 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:
- 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. This gas-permeable layer is used only in homes with basement and slab-on-grade foundations; it is not used in homes with crawlspace foundations.
- 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 (with seams sealed) is placed directly over the crawlspace floor.
- Sealing and caulking: All below-grade openings in the foundation and walls are sealed to reduce soil-gas entry into the home.
- Vent pipe: A 3- or 4-inch PVC pipe (or other gas-tight pipes) runs from the gas-permeable layer through the house to the roof to safely vent radon and other soil gases to the outside.
- Junction boxes: An electrical junction box is included in the attic to make the wiring and installation of a vent fan easier if, for example, you decide to activate the passive system if your test results show an elevated radon level (4 pCi/L or more). A separate junction box is placed in the living space to power the vent fan alarm. An alarm is installed along with the vent fan to indicate when the vent fan is not operating correctly.