Understanding and Managing Vacant Houses in Support of a Material Stock-Type Society—The Case of Kitakyushu, Japan

From a sustainable material management perspective, vacant houses represent material stock and still have potential in the circular economy. This article addresses two aspects of understanding and managing vacant houses: the difficulty of understanding their spatial and temporal patterns and the management of the social costs behind the phenomenon of vacant houses. These aspects are approached by combining a 4D GIS analysis with expert interviews and additional qualitative tools to assess the spatial and temporal dimension of vacant houses. Furthermore, this manuscript presents a tool to estimate the obsolete dwelling material stock distribution within a city. The case of the city of Kitakyushu demonstrates the relationship that exists between the historical trajectories of housing norms and standards, such as comfort, cleanliness, safety, and convenience, and the dynamics of the built material stock and demography for three selected neighbourhoods. The results show that the more locked-in a district is in terms of “obsolete norms and codes”, the more likely it is that the obsolete stock is dead, and consequently, urban mining should be considered. The article concludes that a revisiting of the norms and standards of convenience and other domains is one of the prerequisites of the transition toward a circular built environment and the prevention of obsolete stock accumulation.