Kuenzel, H.H.Kuenzel2022-03-082022-03-081996https://publica.fraunhofer.de/handle/publica/303354The invention relates to an insulation panel made of rigid foam for building a reverse roof (R roof), said insulation panel consisting of non-extruded, thermoplastic rigid foam and whereby at least one surface of the insulation panel is modified in such a way that said surface has a water vapour diffusion resistance greater than the core material of the insulation panel.de608624690patent1994-4439415