We are in the process of (maybe) buying a home. It is a newer (2007) home in Northern Wisconsin with an insulated concrete form (ICF) basement in red clay. We just got the radon test back and the 2 day average is at 5.1 pci/l. I am not concerned about the levels – mitigation devices will happen. My concern is why?
Is the presence of radon in a newer home an indicator of a not tight / poorly constructed basement or is it an indicator of a very tightly built basement/home?
I have seen some people arguing that it indicates the basement is not 'tight' / poor construction – if a basement is properly built radon should not be able to enter. However, there was no sign of water in it – and it was as dry a basement as I have seen. But, with ICF you can't see voids or cracks in the wall – but then again, no sign of moisture.
Others argue that because a home is tight it tends to trap more stuff and what does get in can't get out. This also seems plausible – there was no air exchanger installed that I saw and most newer homes seem to have them up here to control moisture. Also the sump/drain wasn't sealed so that could be a point of entry.
Best Answer
Concrete is Porous this is why we put vapor barriers down and foundation drains because if there is moisture it will permeate the concrete. Doesn’t that mean the foundation is not done correctly? No concrete is porous and if moisture can make it through it is much easier for a much smaller substance to make it through. Not only can it come just through the ground but if the well is close To the house this is a source that the radon has an easy exit compared to going through many feet of earth. If your home has an internal sump pump there is another entrance point. So radon in the home is not an indication of the quality of the foundation. Epoxy coating the floor can help as this helps to seal the floor but now the walls we can’t forget about the walls.