Thermally insulated facades are standard today and are also indispensable for climate protection reasons. The most common type of thermal insulation is done with styrofoam panels and a thin outer plaster over them. In case of temperature fluctuations, condensation is formed very easily, because the heat from the interior of the building is no longer released to the outside. Algae and fungi like to settle on the moist surface and form a grey-greenish to black covering. It does not affect the durability or load-bearing capacity of the building, but its beauty. In order to avoid such coverings, thin plaster is therefore routinely equipped with biocides, which prevent the formation of fungi and algae for a few years. In heavy rains, however, the active ingredients are washed out and enter the soil and water.
The Bureau for Chemical Engineering TB-Klade has carried out a study on behalf of the Vienna Ombud’s Office for Environmental Protection in order to assess the potential effects of these biocides on the environment and health. The study covers the following topics: evaluation of inherent properties of relevant biocidal agents; quantity relevance; encapsulation, leaching and environmental input; planning measures; biocide-free thermal insulation composite systems and facade plastering. In order to avoid or at least reduce the use of biocidal active ingredients in building facades and the associated risks for processors and the environment, strategy recommendations are made. The study can be found on the webpage of the Vienna Ombud’s Office  or can be downloaded here:
PDF document: Decision support for the assessment (only german)