Tips: Addressing Indoor Environmental Concerns During Remodeling, Radon Issues

Test your homes for radon. Radon is the second leading cause of lung cancer in the United States. You can't see or smell radon, but it's not hard to measure the level of radon in your home. Testing is easy and should only take a little of your time. For more information, see EPA's Radon Page (, the publications A Citizen's Guide to Radon (, the Home Buyer's and Seller's Guide to Radon ( and the Consumer's Guide to Radon Reduction ( EPA recommends fixing your home if a test shows radon levels in your home exceed the action level of 4 picocuries per liter of air (pCi/l). If you are building an addition (or a new home) there are techniques you can use to help prevent high radon levels.

Why Should You Build Homes with Radon-Resistant Techniques?

They Make Homes Safer from Radon.

These construction techniques help block radon from entering the home. The occupants will benefit from lower radon levels in their new home.

They Are Easy to Upgrade When There is a Need to Increase the Radon Reduction.

If high radon levels are found, the techniques allow for easy and inexpensive installation of a fan for increased radon reduction in the home. Every new home should be tested for radon by the homeowner after occupancy.

They are Cost-Effective for Home Buyers

It is more cost-effective to include radon-resistant techniques while building a home, rather than installing a radon reduction system in an existing home.

They May Improve The Home's Energy-Efficiency.

Radon-resistant construction techniques are consistent with state-of-the-art, energy-efficient construction. When using these techniques, follow the Model Energy Code (or other applicable energy codes) for weatherization, which will result in energy savings and lower utility bills.

What are Radon-resistant construction techniques?

The techniques may vary for different foundations and site requirements, but the basic elements are:

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.

If you have further questions about Radon, please call the National Radon Information Line at (800) 767-7236.

This article originally appeared in the 08/01/2005 issue of Environmental Protection.

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