Over two millions of public houses are managed by local governments in Japan, and more than half of the total stock requires updating and improvement because of their physical deterioration and mismatching of current housing standards. Actually, they increasingly implemented renovation projects for existing public houses with financial support from the national government. However, there are little wooden public houses renovated with the governmental support. That's because the overwhelming majority of the public houses was those constructed of reinforced concrete or concrete blocks, and those constructed of wood are likely to be newly built compared to the other types of construction. Given that more wooden public houses will past the statutory durable lifetime (30 years for wooden public houses) in the near future, it is increasingly important for local governments, most of which faced financial difficulties, to maintain existing wooden public houses as community assets.
This study aims to show real situation of maintenance and management of wooden public houses and to offer basic knowledge which can contribute to proper management of them. As preliminary research, the author conducted analysis of nationwide statistical data of public houses. The results indicate that stocks of wooden public houses was basically divided into two: those constructed before 1970 and those after 1980. The former was constructed by standardized planning and design for resolution of serious accommodation shortage just after WWII, and the latter was characterized by original design and adoption of traditional construction methods and materials and expected to be a regional symbol of dwelling environment. The results also showed that small municipalities, particularly those managing less than 100 units of public houses, are largely divided into two groups: those at a very high rate of wooden public houses and those with a very low rate.
As case research, the author selected ten municipalities, which varies in population from less than 10,000 to more than 800,000, and where most of the wooden public houses were built after 1980. According to analysis of the relevant documents including long-life plans of public houses, which are mandatory documents for application for national governmental support, wooden ones are likely to be planned to be utilized continuously even if they past the statutory durable lifetime. Based on the detailed interviews with the officials at the local governments, most of the municipalities pointed out physical deterioration of wooden public houses, and necessities for any refurbishment and renovation. Out of the refurbishment and renovation works after 2000, (1) external wall refurbishment, (2) roof refurbishment, (3) installment of hot-water supply equipment, (4) maintenance of water supply and drainage and (5) termite extermination were pointed out as particularly costly works. But because of difficulties to secure a sufficient budget, most of these works had to be fully financed by themselves.
It was found that the municipalities have difficulty to apply for governmental financial support for refurbishment and renovation works of wooden public houses, and they have to adopt an appropriate refurbishing method to construction methods and materials in existing buildings. To implement refurbishment and renovation works for wooden public houses effectively, they should be appreciated from a viewpoint of life cycle cost, and manuals or guidelines for officials at local governments which describe periodic works and expected costs should be organized.