Does radon come from building materials?

There may be a few building materials that will emit small amounts of radon gas, such as granite, concrete, gypsum board (sheet rock), bricks, and field stone. However, this is RARELY the case because most of these materials are very dense. This means that if there is radon-producing radium in these materials, only a small amount of the radon gas near the surface ever makes it out into the environment. Most of the radon gas decays while trapped below the surface. Radon gas has an approximately 92 hour half-life and in 8 half-lives, most of it is "dead." In almost all cases of elevated indoor radon levels, the culprit is the underlying soil. We have heard of a few homes whose walls are built entirely of stone that have almost NO indoor radon. We have also heard of a few that have elevated levels. It is not easy to determine if the radon is coming from only the walls or if it is a combination of the walls and the underlying soil. To know for certain requires a skillful tester using ...  more