Modelling climate related performances of building wall coatings and understanding the portability of the “Künzel” rule in different climates

Abstract How may a coating affect the hygrothermal performance of building envelope in different climates? Years ago, Helmut Künzel, one fathers Building Physics, proposed, simple, well-known rule, relating two characteristics coating: its water absorption coefficient and vapour diffusion. The “Künzel rule” (and associated diagram), based on model confirmed by field tests German climate, set an upper limit to both parameters their product, became standard practice among experts, practitioners manufacturers, many European countries. This paper proposes results analysis aiming verify portability other climates is extensive simulation performances reference wall six climatic conditions.