[en] Highlights: • The radon diffusion coefficients of waterproofing insulations do not differ within Europe. • The original radon resistance calculation gives false values for 51% of insulations. • Radon resistance has been confirmed as a suitable parameter for designing insulations. • 95% of widely-used waterproofing insulations have sufficient radon resistance. • A method prescribing several minimum radon resistance values has been verified. - Abstract: This paper presents radon diffusion coefficient values and radon resistance values determined for 650 widely-used waterproofing materials divided into 29 groups according to their chemical composition. The reliability of two different approaches for determining the radon resistance is discussed, and differences between the two approaches are identified. A comparison between the radon resistances of waterproofing materials and the requirements prescribed by various building standards indicates that some requirements are unnecessarily strict. It is shown that the most effective approach for setting the requirements is to prescribe several minimum radon resistance values in dependence on the parameters of the building and the subsoil.