Radon in slab on grade construction

Radon in slab on grade construction. Is Radon capable of passing through slab on grade construction with a typical vapor barrier underneath the concrete? Thanks.

In fact, depending on where the aggregate was mined, and what it contains, the concrete itself may contain Radon, such as Granite (countertops) may, as well as in the water you bath/shower in and cook with!


Aren’t most basements slabs placed “on grade”?
I know they are different types of foundations, but the comparison is still the same.



Walls for slab on grade construction sit on the slab above grade. Basement floors are poured inside the foundation walls below grade. The radon in homes enters through physical holes in the foundation it does not “pass through” solids. Modern home construction considers this when slabs are poured. My experience in testing slab on grade in my area reveals consistently low Radon levels.

1 Like

My experience testing where I am is that slab on grade foundations are just as likely to have high radon as any other foundation. More than once I’ve tested adjacent buildings, slab on grade residence was high, basement residence was low. Also had the opposite combination. I cannot predict radon levels based on foundation type. That’s why you have to test.


This has been my experience as well.


Not me. I cannot remember the last slab home I tested that was elevated. However, any one inspector is a tiny sample size. I recommend test them all…and so does the EPA.


That is it. One inspector is limited to a specific geological region. Even if you were on the border of two different geological areas with diverse results it would be hard to achieve a sample size that could predict results. The only way to know is to test.


The vapor barrier is going to have a lot more of an effect on the readings than SOG vs basement.

1 Like

Thanks guys!