Learn. Radon-resistant new construction.

 
The EPA created a map of radon zones to assist national, state, and local organization in targeting resources and implementing radon-resistant building codes.  The zones are designated by county based on 5 factors: indoor radon measurements, geology, aerial radioactivity, soil permeability, and foundation type.  

While North Carolina currently does not have any radon-related building codes in place, Wake County has been designated by the EPA as a moderate risk zone (Zone 2).  Zone 2 counties have a predicted average indoor radon screening level of 2-4 pCi/L.

According to the EPA, "This map is not intended to be used to determine if a home in a given zone should be tested for radon.  Homes with elevated levels of radon have been found in all three zones.  All homes should be tested regardless of geographic location."  [Visit the EPA's website for more information about the EPA Map of Radon Zones.]

If you plan to build a new home, build it radon-resistant.

While not required by code, many Triangle-area builders are utilizing radon-resistant construction techniques.  These techniques combine common construction methods and materials to seal entry points and route soil gases outdoors to minimize the entry of radon into the home. The following are a few of many techniques that can be utilized:

• Aggregate - Spread at least 4" of clean aggregate under all areas within the foundation walls that will be covered by a concrete slab.
• Soil-gas retarder - 6 mil polyethylene sheeting should be placed over the aggregate and be sealed to and secured around all penetrations.  This helps to keep moisture in the concrete, enabling it to fully cure while minimizing cracks.  In a crawl space, this plastic sheeting is sealed to all foundation walls, pillars, and piers.
• "T" vent pipe - a "T" fitting made of PVC piping is inserted into the aggregate through the concrete slab (or the crawl space vapor barrier). This pipe is generally vented through the roof and can remain passive (no fan) or be activated with the addition of a radon mitigation fan.

It is safer for your family and more cost-effective to prevent radon from becoming a problem.  Some possible benefits of radon-resistant new construction are outlined below.

Reduced lung cancer risk.

Radon-resistant techniques reduce indoor radon levels, thus reducing the amount of radon that the home's occupants inhale.  The lower your radon exposure, the lower your risk of developing lung cancer.

Improved system aesthetics.

When radon-resistant construction features are incorporated into the design of a home, they can be hidden from view.  Pipes can be routed between walls to minimize visibility of the system from both the interior and exterior of the home.

Controlled basement moisture.

A secondary benefit of radon-resistant construction may be reduced basement moisture.  The entry of water vapor through the slab foundation is often a source of moisture in basements.  A mitigation system that prevents radon-laden soil gases from entering the basement may also minimize the entry of water vapor into the basement. 

Increased home value.

When a home is built radon-resistant, potential buyers can be more confident in their level of radon exposure.  Informed buyers will view this as a positive feature, knowing that any potential radon issue could be resolved easily and aesthetically.

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Radon Facts
Radon Health Risks
Radon & Real Estate
Radon & New Construction


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