4. I'm buying or building a new home. How can I protect my family?
a. 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 at the time of 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:
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make upgrading easy: 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. |
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are 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. |
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save money: 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 further reducing radon levels. In an existing home, it usually costs between $800 to $2,500 to install a radon mitigation system.
b. 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:
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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.
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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.
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sealing and caulking: All below-grade openings in the foundation and walls are sealed to reduce soil-gas entry into the home.
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vent pipe: A 3- or 4-inch PVC pipe (or other gas-tight pipe) runs from the gas-permeable layer through the house to the roof to safely vent radon and other soil gases to the outside.
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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 properly.
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5. How can I get reliable radon test results?
Radon testing is easy and the only way to find out if you have a radon problem in your home.
a. Types of Radon Devices
Since you cannot see or smell radon, special equipment is needed to detect it. When you're ready to test your home, you can order a radon test kit by mail from a qualified radon measurement service provider or laboratory. You can also hire a qualified radon tester, very often a home inspector, who will use the radon device(s) suitable to your situation. If you hire a home inspector, make sure you hire a qualified InterNACHI member -- specifically, an IAC2 certified air-quality professional. The most common types of radon testing devices are listed below.
Passive Devices
Passive radon-testing devices do not need power to function. These include charcoal canisters, alpha-track detectors, charcoal liquid scintillation devices, and electret ion chamber detectors, which are available in hardware, drugstores, and other stores; they can also be ordered by mail or phone. These devices are exposed to the air in the home for a specified period of time, and then sent to a laboratory for analysis. Both short-term and long-term passive devices are generally inexpensive. Some of these devices may have features that offer more resistance to test interference or disturbance than other passive devices. Qualified radon testers may use any of these devices to measure the home's radon level.
Active Devices
Active radon-testing devices require power to function. These include continuous radon monitors and continuous working-level monitors. They continuously measure and record the amount of radon and its decay products in the air. Many of these devices provide a report of this information, which can reveal any unusual or abnormal swings in the radon level during the test period. A qualified tester can explain this report to you. In addition, some of these devices are specifically designed to deter and detect test interference. Some technically advanced active devices offer anti-interference features. Although these tests may cost more, they may ensure a more reliable result.
b. General Information for All Devices
A state or local radon official can explain the differences between devices, and recommend the ones which are most appropriate for your needs and expected testing conditions.
Make sure to use a radon measurement device from a qualified laboratory. Certain precautions should be followed to avoid interference during the test period. See the Radon Testing Checklist for more information on how to get a reliable test result.
Radon Test Device Placement
The EPA recommends that testing device(s) be placed in the lowest level of the home suitable for occupancy. This means testing in the lowest level (such as a basement) which a buyer could use for living space without renovations. The test should be conducted in a room to be used regularly (such as a family room, living room, play room, den or bedroom); do not test in a kitchen, bathroom, laundry room or hallway. Usually, the buyer decides where to locate the radon test, based on their expected use of the home. A buyer and seller should explicitly discuss and agree on the test location to avoid any misunderstanding. Their decision should be clearly communicated to the person performing the test.
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c. Preventing or Detecting Test Interference
There is a potential for test interference in real estate transactions. There are several ways to prevent or detect test interference:
- Use a test device that frequently records radon or decay-product levels to detect unusual swings.
- Employ a motion detector to determine whether the test device has been moved or if testing conditions have changed.
- Use a proximity detector to reveal the presence of people in the room, which may correlate to possible changes in radon levels during the test.
- Record the barometric pressure to identify weather conditions which may have affected the test.
- Record the temperature to help assess whether doors and windows have been opened during the test.
- Apply tamper-proof seals to windows to ensure closed-house conditions.
- Have the seller/occupant sign a non-interference agreement.
Home buyers and sellers should consult a qualified radon test provider about the use of these precautions
