About the Radon-Resistant New Construction (RRNC) Builder Directory

On this page:


The directory provides an opportunity for builders who are using RRNC techniques to reach home buyers who are looking for new homes that may reduce exposure to radon. The directory is a one-stop service for home buyers looking to find builders using RRNC techniques.

Some builders incorporate RRNC techniques voluntarily while others do it to meet code requirements. EPA encourages all builders who use the recommended radon-resistant techniques to be listed in the new Radon Resistant New Construction Directory of Builders.

EPA is not endorsing or promoting any individual builder or home. The information on the directory pages is provided as a public service.

How to qualify for the directory

To qualify for listing in the directory, a builder must use RRNC techniques described in one of the following codes, standards, or reference documents. Please read through the code information and techniques, then click on the button at the bottom of the page when you are ready to sign up.

  1. ASTM International Exit(replaces EPA's previous Model Building Techniques and Standards)

While following any of the three primary codes that include radon resistant construction is sufficient to qualify for the Directory of Radon Builders, EPA believes that ASTM E1465-08 has some advantages over the other codes. Using ASTM E1465-08:

  • Allows more flexibility of installation
  • Provides a more effective radon reduction system
  • Increases the life expectancy and durability of mechanical equipment
  • Guarantees results from required testing
  1. The International Residential Code (IRC) Exit

The IRCincludes Appendix F−Radon Control Methods. The International Building Code (IBC) is also available for purchase.

  1. The National Fire Protection Association (NFPA) Exit

The NFPA codes and standards are available in read-only format on line. While the techniques may vary for different house foundations and building site requirements, the five basic features that builders should include to prevent radon from entering a home are:

  • Coarse Gravel or Equivalent (Gas Permeable Layer): Use a 4-inch layer of clean, coarse gravel or equivalent permeable material (such as geo-textile matting) beneath the slab or flooring of a new house to allow the soil gases, including radon, to move freely underneath the house.
  • Plastic Sheeting or Vapor Retarder: Place a 6 mil. polyethylene sheeting over the gravel layer or place over the crawlspace floor.
  • Sealing and Caulking: Seal all openings in the concrete foundation floor and walls, including the slab perimeter crack, with polyurethane caulk to reduce radon and other soil gas entry into the home.
  • Vent Pipe: Run a 3-inch or 4-inch solid PVC Schedule 40 pipe from the gas permeable layer (stubbed up when the slab is poured) through the house’s conditioned space and roof to safely vent radon and other soil gases above the house. This pipe is labeled "Radon System." Your plumber or a certified radon professional can do this. For service providers in your area, visit:
  • Electrical Junction Box Outlet: Install an electrical junction box (often in the attic) for later installation of a vent fan if a radon test shows elevated levels in the home.
  • Fan: Install a fan to turn a passive RRNC system into an active system when a radon test shows elevated levels of radon in the home.
Yes, My company wants to qualify for the EPA Directory of Builders Using Radon-resistant New Construction Techniques. Click Here to begin the process

Top of Page