How to Install a Radon Barrier - Slab Floors
If in the kind of area where it's a good idea to install a vapor barrier against radon ingress, (check out the Radon maps by state and province page to find out here) we can't stress enough how important it is to test for radon, or better still to continually monitor for high radon levels. It's so important for health, and it's so easy to miss a small detail during construction that lets radon into your basement or home, it's reassuring to know that there's such a huge selection of SMART radon monitors available that keep a constant eye on the levels in the home. Take a look here for the best choice and prices on SMART radon monitoring equipment and their Apps.
Polyethylene barriers below slab floors serve two purposes - to prevent moisture from wicking into concrete and disbursing it into homes, also to create a radon barrier. Radon gas occurs naturally in the soil, a result of decomposing uranium in the ground. So it's everywhere, but more intense in some locations than others.
Rather than using the typical 6 mil polyethylene as a sub-slab vapour barrier, we used a 10 mil barrier and a radon evacuation stack to lower radon gas levels in homes, research shows (see below) that thicker membranes offer more effective protection.
In this video we are installing a 10 mil vapour barrier but we would probably use a thick vapor barrier like this one in future as the cost and quality is superior. The thicker barrier is not only better for mitigating soil gas, but it is far more durable during the construction phase than the 6 mil poly.
More on radon protection:
From the EcoHome Green Home Building Guides