Radon-Resistant New Construction

Radon occurs naturally in soil and rock and can enter buildings through openings in the foundation floor or walls. Long-term exposure to elevated indoor radon levels can increase your risk of lung cancer, and since any home could have a problem, all homes should be tested.


The good news is, when elevated radon levels are found, they can be reduced, and new homes can be built using radon-resistant construction techniques.  These construction techniques are recommended for all homes being built in Zone 1* counties and they may be practical in some areas of Zone 2 counties as well.


If you are building a home in a Zone 1 county, talk to your builder about including a passive radon control system in the construction process.  It is an inexpensive addition to the total cost of your new house and is an easy way to help reduce the risk of a radon problem, and as of July 2001, it's a requirement of the Michigan Residential Code.


If an elevated radon level is found after the home is completed, the problem can still be fixed.  Your passive radon control system can be "activated" to provide further radon reduction.  This is accomplished by adding an in-line fan to the existing system, and this simple upgrade will almost always achieve results that are well below the U.S. Environmental Protection Agency guideline of 4 pCi/l (4 picocuries per liter).


Radon-Resistant Construction Is Easy and Inexpensive!


There are four simple techniques specific to radon-resistant construction, and when combined with other good building practices, the process of building a radon-resistant home is relatively easy and inexpensive.


Four Simple Steps

  • Gas Permeable Layer -- -- Install a layer of clean gravel or aggregate beneath the slab or flooring system to allow soil gases to move freely beneath the home.

  • Impermeable Layer -- Cover that layer with a vapor barrier (plastic or polyethylene sheeting) to help prevent radon and other soil gases from entering the home.

  • Vent Pipe -- Run a 3-inch or 4-inch PVC pipe from the gas permeable layer up through the roof.

  • Caulking and Sealing -- Caulk and seal all openings in the foundation floor or walls to reduce the potential for soil gas entry.


If not already required by code, a builder might also add an electrical junction box in the attic in case a fan is needed to activate the system.


The average cost of installing a passive radon control system will be $350-$500.   If you're building in a Zone 1 county, make sure your builder uses these techniques to make your new home radon-resistant!  Then test it to determine the radon levels, and if there's still a problem, simply have the system activated (retest, just to be sure).  Though builders are not required to use radon-resistant techniques in homes built in Zone 2 or Zone 3 counties, you may want to request that the builder do it anyway.


Benefits of a Radon Control System:

  • The techniques are simple and inexpensive.

  • They typically reduce radon levels by about 50%.

  • They often reduce concentrations of other soil gases as well.

  • They can increase energy efficiency.

  • They often help control moisture and sometimes even eliminate that "musty smell" common in basements.

  • If elevated radon levels are found, the passive system can easily be upgraded to an active system that will provide further radon reduction.


For more detailed information about radon-resistant new construction, check out the following:


EPA's Radon Website

The above-listed documents are also available in print form from the Michigan Department of Environmental Quality Indoor Radon Program at 800-RADON GAS/800-723-6642.  Also available in print form are:


Radon-resistant Construction Techniques for New Residential Construction, Technical Guidance           

Radon Prevention in the Design and Construction of Schools and Other Large Buildings (Third Printing with Addendum)


[*Zone 1 means a county has a high radon potential.  There are nine Zone 1 counties in Michigan:  Branch, Calhoun, Cass, Hillsdale, Jackson, Kalamazoo, Lenawee, St. Joseph, and Washtenaw.  Visit Radon Potential for more information.]