Intro to Radon Abatement
Radon is a naturally occurring radioactive gas that is known to cause cancer in high doses. The risk associated with radon in residences remains uncertain, but the Environmental Protection Agency has recommended that every existing home be tested for radon and that action be taken if the test shows radon concentrations greater than 4.0 picocuries/liter of air.
Check Local Sources
The EPA also recommends that new homes be built with radon resistant elements (Radon Elimination Strategies, below). This recommendation has been adopted as a requirement by some codes. These precautions are more important in areas where higher concentrations of radioactive materials are present in local rock. Check with state public health and environmental agencies about testing and risks in your area.
The EPA-recommended details for radon abatement call for poly to be placed above the gravel subbase and below the slab. Placing concrete directly on plastic can contribute to slab cracking due to uneven shrinkage and curling. For that reason, consider putting a layer of damp compacted sand above the poly before placing the concrete see Subslab Vapor Barriers in Subgrade and Subbase).
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