Maintaining and expanding the market potential for bio-based building products in indoor and outdoor construction uses remains a key activity for European industry in the forestry and biotechnological sector. Performance data for many “environmental friendly” building materials are lacking as well as suitable comprehensive test methodologies to determine their resistance against mould, stain, and decay. The similarity in terms of decay hazard, resulting response on climatic loads and thus performance of different bio-based building materials has not yet been recognised adequately, wherefore this Action will provide a platform for networking and scientific exchange between different disciplines, such as material sciences, wood technology, biology, biotechnology, building physics and engineering. Consumer demands and preferences, which might serve as limit states to develop service life prediction and performance models, will consider aesthetical aspects as well as the functionality of building assemblies. A coordinated effort to put the issue of biodegradability of organic building products on the agenda will contribute to the control and prevention of this imminent threat to use bio-based building materials, which in turn could severely damage a pan-European low carbon building agenda.