Lifetimes of Buildings in Japan

Abstract Ascertaining the lifetime distribution of a nation’s buildings is critical for estimating their stock flow, determining their environmental impacts, and exploring future predictions and effective measures. It is particularly necessary in climate-change-mitigating measures such as the estimation of wood carbon stock dynamics. This work uses the latest data on building stocks and inflows to identify the lifetime function and half-life of all wooden and non-wooden buildings existing in Japan from 1964–2020. The log-normal distribution of wooden buildings proved to be the most suitable lifetime function, with a half-life of 38 years in 1964, 56 years between 1965 and 1996, and 63 years between 1997 and 2020. On the other hand, the log-normal distribution resembled exponential distribution (first order decay) and was the most suitable for non-wooden buildings, with half-life of 22 years in 1964, 33 years between 1965 and 1990, and 52 years between 1991 and 2020. The lifetimes of both wooden and non-wooden buildings have increased over the course of the past half-century. It is important that future research uses these lifetime functions to explore future predictions of building stock based on new building demand, changes in lifetime, and effective climate change measures.