Even in my state I don’t think it’s required everywhere. In the mountains and the Piedmont there is a risk although it’s not common, but I think in the coastal plain on the sandy soil it’s uncommon. IIRC for our state the more granite in the ground the higher the risk. Having a crawlspace foundation is also better than a basement or a slab foundation because it gives a space that can easily be ventilated before the gas enters the living space of the home.
I think I saw a study once that granite countertops may offgas some radon. Maybe there’s not enough granite in the average home to cause concern.
Interestingly, the NZ average data rose from 16 to 23 between the 80s and 2016, I wonder if it’s related to the rise in concrete slab houses where raised houses on piles with a crawlspace were previously the primary way houses were built. Granite countertops possibly play a part too.
Even in my state I don’t think it’s required everywhere. In the mountains and the Piedmont there is a risk although it’s not common, but I think in the coastal plain on the sandy soil it’s uncommon. IIRC for our state the more granite in the ground the higher the risk. Having a crawlspace foundation is also better than a basement or a slab foundation because it gives a space that can easily be ventilated before the gas enters the living space of the home.
I think I saw a study once that granite countertops may offgas some radon. Maybe there’s not enough granite in the average home to cause concern.
Interestingly, the NZ average data rose from 16 to 23 between the 80s and 2016, I wonder if it’s related to the rise in concrete slab houses where raised houses on piles with a crawlspace were previously the primary way houses were built. Granite countertops possibly play a part too.
Could easily be better weatherproofing
One of the reasons I never worried about radon is I live in an older house that leaks lots of air.