Analysis & strategy recommendations
Thermally insulated facades are now standard and indispensable for climate protection reasons. The most common type of thermal insulation is done with polystyrene panels and a thin exterior plaster over them. Condensation forms very easily when the temperature fluctuates because the heat from the inside of the building is no longer released to the outside. Algae and fungi then like to settle on the often-moist surface and form a grey greenish to black coating. It does not affect the durability or load-bearing capacity of the building, but it does affect its beauty. To avoid such coatings, thin plaster is therefore routinely equipped with biocides that prevent the formation of fungi and algae for several years. However, during heavy rainfall, the active ingredients are washed out and end up in the soil and water.
The Technical Office Klade has prepared a study on behalf of the Viennese Ombud office for Environmental Protection (WUA) to assess the potential effects of these biocides on the environment and health. The study covers the following topics: Hazardous properties of biocidal active substances used and their relevance to quantity; encapsulation, leaching and environmental input; planning measures; Biocide-free external thermal insulation composite systems or façade plaster. To avoid or at least reduce the use of biocidal agents in building facades and the associated risks for processors and the environment, the study provides strategy recommendations.