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.  If you are building a home, 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 in Zone 1* counties.  However, radon is an issue in every county and radon resistant construction techniques are recommended for all homes statewide.


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 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.  Special skills are not required to perform this type of work.  These techniques and materials are commonly used in the construction of a new home.


Simple Steps

  • Gas Permeable Layer  ̶  Install at least a 4” 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 preferably a 4-inch PVC pipe routed vertically (no turns) through the middle of the house from the gas permeable layer up through the roof.
  • Caulking and Sealing  ̶  Caulk and seal all openings in the foundation floor or walls (including the slab perimeter) with a polyurethane caulk to reduce the potential for soil gas entry.
  • Junction Box  ̶  Install an electrical box (outlet) in the attic incase a fan needs to be added later to reduce radon levels further.


The average cost of installing a passive radon control system will be $350-$500.   If you're building a home, 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 by installing a radon fan.  Though builders are not required to use radon-resistant techniques in homes built in some 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:

RRNC Essential Components Inspection Form

ANSI-AARST National Standards

EPA's Radon Website

Building Radon Out

Some documents are also available in print form from the Michigan Department of Environment, Great Lakes, and Energy Indoor Radon Program at 800-RADON GAS/800-723-6642. 


[*Zone 1 means a county has the highest radon potential based on EPA Map of Radon Zones.  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.]