Preventing mold formation and unwanted growth on façades

© Fraunhofer IBP
© Fraunhofer IBP

WUFI Bio uses a traffic light icon for the assessment of mold growth risks. In the example (below), the assessment was done for a retrofitted flat, in which only the old windows were replaced by new ones, without additionally adding thermal insulation to the building envelope.

Mold growth represents a potential health hazard due to its production and spread of pathogenic substances. To avoid mold, it is important to develop prevention strategies that take into account both the preconditions for mold growth and the actual transient boundary conditions. WUFI® Bio is a bio-hygrothermal calculation method based on known climatic boundary conditions. It is used to assess the risk of mold formation and devise strategies that avoid its occurrence.

In contrast to the situation in building interiors, microbial growth on façades is usually a mere esthetic problem. The improved heat insulation of exterior components increases surface moisture and therefore the risk of algal and fungal growth. Fraunhofer IBP experts carry out chemical, biological and building physics research into ways of curbing and eliminating this growth.



Microbial growth on insulated façades

For manufacturers of composite thermal insulation systems, microbial growth on thermally insulated façades still poses a problem. Approaches to solving the problem using building physics are all based on the idea of reducing moisture on the surface of the façade.



Surface moisture

Wall insulations reduce the amount of heat transfer from the building’s interior. In terms of building physics, this increases the probability that condensation might form on the outer surface of the façade due to the cooling effect of long-wave emission of heat during the night.

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Martin Krus

Contact Press / Media

Prof. Dr. Martin Krus

Fraunhofer Institute for Building Physics IBP
Fraunhoferstr. 10
83626 Valley, Germany

Phone +49 8024 643-258

Fax +49 8024 643-366