Obsolescence, defined as the process of declining performance of buildings, is a serious threat for the value, the usefulness and the life span of built properties. Thomsen and van der Flier (2011) developed a model in which obsolescence is categorised on the basis of two distinctions, i.e. between endogenous and exogenous cause-effect relationships and between physical and behavioural cause-effect relationships. In this way, the model presents a classification of underlying factors of obsolescence. However, these underlying factors, more specifically the underlying cause-effect relations, are still a black box. In this paper, the box is further disclosed by tracking back the underlying processes, resulting in a series of prototypes of detailed hypothetic cause-effect mechanisms. Applied to the adapted model, the results are initially tested on an iconic chocolate factory. Conclusions are drawn about the results and more generally about the usability and the further development of the model.