Architectural coatings enhance the functional and aesthetical durability of building materials by protecting their surface. Consequently, paints and coating applied on the exterior of a residence, or a commercial building not only add to the aesthetics of the structure but also defend it against heat, UV, harsh winters, soaking rain, and other adverse weather conditions. The commonly used surface treatments consist of mineral oil binders and many environmentally unwanted ingredients, therefore environmentally friendly alternatives are within the interest of architects, constructors, and end-users.

Recent progress in biomimetics allows the fabrication of man-made surfaces with similar properties as biological ones. Engineered living materials (ELM) use an alternative (living) set of building blocks compared with conventional man-made materials. ELMs, being a combination of artificial and biological components, are the most relevant contemporary revolution in materials science and engineering. Due to unique functionalities and outstanding properties, they outperform current examples of “smart materials”. The convergence of engineering, biology, and materials science allows the integration of unicellular and multicellular organisms into next generation engineered systems. ELM's possess enormous potential as a new generation of active materials in sustainable built environments or as an integrated network of living sensors to monitor the presence and movement of pollutants and pathogens [1].

The ARCHI-SKIN project takes a bio-inspired approach and aims to generate completely new solutions for architectural coatings. A prototype microbial coating based on biofilm built by the ubiquitous, yeast-like, oligotroph fungus, Aureobasidium pullulans is under development. The concept presented in Figure 1, is based on a technically applicable, controlled, and optimized biofilm formation that effectively protects the substrate surfaces, assuring optimal service life performance and different functionalities including self-healing. This contribution presents ambitions, challenges, and first results related to the development of a living coating system for architectural surfaces.