Exploring the interplay of climate and hygrothermal risk for insulated wall assemblies in the iberian peninsula

On the road towards an energy neutral building stock, increasingly demanding insulation levels are advised for both new and retrofitted buildings. While centuries of past experience have led to vernacular construction methods suited to local climates, the incorporation of thermal insulation to existing walls fundamentally alters their moisture balance and drying capacity. The impact of insulation assemblies on moisture risk is relatively well studied for cold climates; however, research and case studies are scarce for the warmer climates of Southern Europe, where such highly insulated walls have been unusual up to now. This paper presents a parametric study evaluating the hygrothermal performance of 3 types of insulated wall assemblies exposed to 5 climates of the Iberian Peninsula. In particular, the influence of climatic parameters on hygrothermal risk is investigated, using transient numerical simulation methods. Results show that the impact of solar irradiation and wind-driven rain over different orientations can outweigh that of temperature and humidity. Moreover, their combined effect can be either beneficial or detrimental, depending on the interplay of the specific climate and type of assembly. Hence, it has been found that simplified assessment methods that do not consider the impact of wind-driven rain underestimate risk significantly for certain scenarios. Finally, the hygrothermal performance of the assessed wall assemblies is evaluated in the context of Iberian climates, discussing possible improvements.