Abstract

External Thermal Insulation Composite Systems (ETICS) contribute significantly to building energy efficiency by increasing thermal insulation, correcting thermal bridges and reducing interior water condensation. Additionally, these solutions protect the structure and thus enhance the durability of the building. The use of ETICS remarkably increased in the last three decades also due to the introduction of new international and national regulations on building energy efficiency (e.g. EU Directive on the Energy Performance of Buildings). ETICS are constantly exposed to weathering (e.g. wind, rain, sun light) and anthropic factors (e.g. graffiti, environmental pollutants), which can lead to cracks, biocolonization and stains and thus affect ETICS durability. However, international technical documents on the evaluation of the effectiveness and durability of ETICS do not consider the possible synergies between these factors, which can trigger and speed up multiple biological, mechanical and chemical degradation processes. With the aim of filling this gap, this paper focused on the water resistance and surface properties of several ETICS surface coatings, verifying possible connections between these factors. The moisture transport properties (capillary water absorption, water vapour permeability, and drying kinetics) and surface properties (colour, brightness and roughness) of some commercially available ETICS were tested. This study is part of a wider research project (WGB_Shield: resistance for water, graffiti and biocolonization of external thermal insulation systems) that aims at the development of ETICS with improved durability in urban environment.