Metrological evaluation of facade coating systems regarding their resistance to microorganism growth

Abstract

Abstract The presence of liquid water on the facade surface significantly contributes to the growth of microorganisms. This issue has become increasingly important with the growing use of thermal insulation in buildings. However, the formation of condensation on these façades is often increased due to low surface temperatures. Therefore, innovative coating systems with special physical parameters have been developed to prevent condensation formation and thus the growth of algae on the facade surface. These coatings should be evaluated with respect to their surface condensation to identify their resistance against condensation. Since no suitable method is available for this purpose, it is necessary to develop a method for controlling the wetness and drying out of façades. This paper presents the development and verification of innovative coating systems, as well as an active facade moisture detection system (ONE). The measuring method is designed to provide long-term non-destructive measurements of surface wetness. The measurement data obtained in this research are used to develop facade materials and coatings that improve their drying properties and the balance between hydrophilic and hydrophobic surfaces. This is aimed at preventing or reducing algae growth on the façade. A case study consisting of four test walls was conducted in Central Germany under real climate conditions to examine the resistance of coating systems with different pigments (conventional and modified pigments) to moisture formation on the surface. The results show that the developed coating system has significant potential to increase surface temperatures, leading to a reduced deviation of the dew point. This can help to prevent the growth of algae on the facade.