Research on the Regeneration Procedure for Reutilizing Vacant Housing Stock in Japan

Abstract

Since the economic development period in the 1960s and ’70s, old buildings were always considered unsuitable because of the risk of earthquakes or due to new social trends. But new construction finally dropped in the ’90s, and the birth rate also declined and the aging population grew instead. The number of vacant housing stocks have been more than doubled in Japan last 20 years, with 500,000 residences increased every year, and the issue of regeneration and reutilization of old buildings has become a focus. Yet it has not been easy to achieve successful outcomes because of many and complex impediments, interfere, such as legal, social, structural, economic, or tax-related reasons. In this study, through unraveling these complex impediments, effective countermeasures are organized and case examples of regenerated buildings that have overcome these barriers are introduced to clarify how each problem can be surmounted, and these regeneration procedures will be drawn in the shape of process planning that visualizes the steps of measures against each problem. There are five main problems: old housing plans against new social needs; degradation of building structure and materials against new building standards; old technical standards against new technologies; existing legally non-conforming buildings against ever-added new building laws; and old building reliability against possible economic value estimated. These five problems are used to clarify the regeneration procedure in order to propel and increase the fruitful utilization of this stock for the future.