Today there are too much lawyers on this world and they are boring themselves to death. And as a consequence, they become politican and find out laws, which we do not need. One such a thing is the radon tightness of closed cell cellular glass.
If cellular glass is vapour tight, we can expect that it is also Radon tight. But this logic is not accepted by our lawyer world. For that reason, GLAPOR has ordered a RADON diffusion experiment with is described in this report.
Indeed, a layer of 50 mm cellular glass is 250 times the diffusion length, which means that Radon cannot diffuse through the cellular glass without decaying in the cellular glass. In that way, it is impossible that Radon decays in the lungs of humans and animals behind the cellular glass.
It is needed to install the boards with hot bitumen (which is also Radon tight) but pinholes in the bitumen remain a small risk in the joints. For that reason, it is advised to work with large boards (GLAPOR cellular glass: 2800 mm x 1200 mm) to reduce the number of joints as much as possible. Dry installation of the boards will only minimally protect against Radon.