Thermal insulation of existing buildings and interstitial condensation: Comparative assessment in different European climate contexts

This study focuses on the introduction of different types of insulation materials into existing building systems in Europe, where the chosen scenarios differ by climate zone and according to the Köppen climate classification. The insulation materials used are specifically: natural fibre materials, mineral fibre materials and artificial materials. The analysis in question was based on the assessment of the risk of interstitial condensation between the existing masonry and the insulation and the WCI [Kg/m2] (Water Content in the Insulation), through various simulations in dynamic mode, over a reference period of 10 years prior to the energy upgrading intervention. The case study buildings were taken from TABULA and divided by climatic zone, for the years of construction from 1945 to 1969 related to the building typology of single-family houses, wherein each building system the insulation was placed towards the warm side with a fixed thickness of 5 cm. The simulations concerned: a) the application scenario, b) the type of stratigraphy chosen, (c) exposure of the existing building system. The outputs generated by the simulations provided the data to determine in which type of building, depending on the insulating materials, interstitial condensation is formed or not. It was shown that only for the climate zones of the cities of Oslo and Brussels, associated with their own building typologies, for the insulating materials: mineral and natural, there is the formation of interstitial condensation.