Discolouration of building facades. A knowledge survey

Microorganisms that grow on facades can cause extensive discoloration, which often poses a problem for home owners as it can provide an aesthetically unfavourable impression of the building. Fouling occurs as a result of a complex process that involves several parameters, including biological factors, climatic factors and factors related to the building. This report describes and discusses these factors and their implications for the incidence of fouling, based on scientifically published research. One chapter of the report deals with cleaning and maintenance of facades. Based on the knowledge available in the literature suggestions are given for further research that can contribute to decreased problems with discoloured facades. Finally, the report provides references to a number of scientific articles categorized by keywords in order to make it easier for those who want to read more on the topic.