CR3 News Magazine 2018 VOL 4: SEPTEMBER Environmental Justice | Page 21

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Radon-Resistant Construction Techniques

For more detailed techniques view Model Standards

and Techniques for Control of Radon in New

Residential Buildings.

All of the techniques and

materials described below are

commonly used in home construction.

No special skills or materials are required when adding

radon-resistant features as a new home is being built.

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:

1.Gravel: Use a 4-inch layer of clean, coarse

gravel below the “slab,” also called the foundation.

This layer of gravel allows the soil gases, which includes

radon, that occur naturally in the soil to move freely

underneath the house. Builders call this the “air flow

layer” or “gas permeable layer” because the loose

gravel allows the gases to circulate. NOTE: In some

regions of the country, gravel may be too expensive or

unnecessary. Alternatives are allowed, such as a

perforated pipe or a collection mat.

oSee Building Radon Out pages 35-40 for more information.

2.Plastic Sheeting or Vapor Retarder: Place heavy duty plastic sheeting (6 mil. polyethylene) or a vapor retarder on top of the gravel to prevent the soil gases from entering the house. The sheeting also keeps the concrete from clogging the gravel layer when the slab is poured.

3.A Vent Pipe: Run a 3-inch or 4-inch solid PVC Schedule 40 pipe, like the ones commonly used for plumbing, vertically from the gravel layer (stubbed up when the slab is poured) through the house’s conditioned space and roof to safely vent radon and other soil gases outside above the house. (Although serving a different purpose, this vent pipe is similar to the drain waste vent, DWV, installed by the plumber.) This pipe should be labeled "Radon System." Your plumber or a certified radon professional can do this. For more information visit:

4.

othe National Radon Proficiency Program, or NRPP

othe National Radon Safety Board, or NRSB

oor your state radon coordinator for service providers in your area.

5.Sealing and Caulking: Seal all openings, cracks, and crevices in the concrete foundation floor (including the slab perimeter crack) and walls with polyurethane caulk to prevent radon and other soil gases from entering the home.

6.Junction Box: Install an electrical junction box (outlet) in the attic for use with a vent fan, should, after testing for radon, a more robust system be needed.

A new home buyer may ask the builder about these features, and if not provided, may ask the builder to include them in the new home. If a home is tested after the buyer moves in and an elevated level of radon is discovered, the owner's cost of fixing the problem can be much more.

https://www.epa.gov/radon/radon-resistant-construction-basics-and-techniques