Obsolescence, defined as the process of declining performance of buildings, is a serious threat for the value, the usefulness and the life span of housing properties. Thomsen and van der Flier (2011) developed a model in which obsolescence is categorised on the basis of two distinctions, namely 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 we try to disclose this. Based on a review of related models concerning the process of declining performance of built property, we present several hypotheses on cause-effect relationships underlying obsolescence of dwellings and discuss their relevance and appropriateness for future research on the topic.