ISO/TS 11665-13:2017 specifies the different methods intended for assessing the radon diffusion coefficient in waterproofing materials such as bitumen or polymeric membranes, coatings or paints, as well as assumptions and boundary conditions that shall be met during the test. ISO/TS 11665-13:2017 is not applicable for porous materials, where radon diffusion depends on porosity and moisture content.