It’s possible a home inspection will reveal the existence of radon gas seeping up through the ground into the living area of the home you want to buy. Radon is known for causing lung cancer, so you don’t want it around. What can you do to decrease the seriousness of the problem? In other words, what do you do to mitigate the radon threat?
Radon resistant techniques can be simple and passive and will lower radon levels when done properly. They can lower levels of moisture and other soil gasses, too. Radon resistant techniques have the additional benefit of making your home more energy efficient and can help you save on energy costs. Save money when a home is first built by not having to deal with the problem later if these techniques are put into place with common building materials.
Even in a new home, radon testing should be done to be sure the level is below 4 pCi/L. If radon levels are high, a passive system can be turned into what’s called an active system by adding a vent fan to reduce radon levels.
You’ll need to find someone who is considered to be a qualified radon mitigator to install radon resistant techniques, whether your home is new or not. Costs will vary, but should be similar to other home repairs you may need to have done.
What are these radon resistant techniques? It’s important to note that this depends on your home’s foundation. Also, if you’re having a house built, ask your builder if they’re using EPA’s recommended approach.
The first radon resistant technique of note is a gas-permeable layer, which is used only in homes with casement and slab-on-grade foundations. It is not used in homes with crawlspace foundations. It usually consists of a four inch layer of clean gravel placed under the slab or flooring system. It’s meant to allow the gas to move freely under the house. Plastic sheeting is placed on top of the gas permeable layer and under the slab to help prevent the soil gas from getting into the home
When a home has crawl spaces, plastic sheeting is placed over the crawlspace floor. This serves as a moisture barrier as well.
Sealing and caulking is another technique. Any below-grade openings in the concrete foundation floor are sealed to reduce the amount of soil gases getting into the home.
When there’s a gas-permeable layer under the home, a vent pipe is put into the gravel and runs through the house and to the roof to vent gases away from the living area. The pipe used is a 3- or 4-inch gas-tight or PVC pipe, or other gas-tight pipe.
If it’s necessary to use a vent fan to reduce high radon levels, an electrical junction box is included in the attic to make the wiring and installation of a vent fan easier. A separate junction box is put in the living space to power the vent fan alarm. That’s because an alarm is installed along the vent fan to indicate when that fan isn’t operating properly.
Your home inspector or other qualified radon mitigation professional should know the best place to put radon test equipment. It should go into the lowest level of the home that’s occupied regularly, such as any place used as a bedroom, play or exercise area, den or workshop. The EPA says testing should not be done in a closet, stairway, hallway, crawl space or in an enclosed area where there’s either high humidity or breezy air circulation. Avoid places like the kitchen, laundry room,bathroom or furnace room.
There’s no way to accurately know the level of radon in the home you’re building, buying or selling unless radon testing is done. Be sure your home inspector or other qualified professional can do the testing for you. You don’t have to put your family’s health at risk from radon.