Architects, construction companies and building owners face a unique challenge to offer newly built and renovated buildings a healthy indoor environment without negatively impacting society, the environment and the economy. During the service lifetime of buildings, natural ageing and eventual damage of materials takes place.
Ageing of the materials is one of the results of environmental processes and involves different chemical, physical and biological reactions of the materials used. Bio-deterioration, e.g. mould growth in buildings is one example of the biological reactions of the materials and it affects their sustainability of the materials.
Algae growth on exterior walls is another example of these biological reactions and affects the aesthetics of a nice building.