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We studied the actual livability of annex-added housing built by Japan Housing Corporation. Japan Housing Corporation started to supply alpharoom-added housing in 1987, and in recent years, Urban Renaissance Agency started to supply annex-room-added housing as an improved alpharoom-added housing. This paper suggests these types of housing can create the space which offers the residents independence, flexibility, privacy, and so on.

The objective of this research is to acquire a basic knowledge of architectural planning, in order to realize the changeability and long-term occupancy sought after for dwellings, from the survey and analysis of actual occupancy records and conditions of apartment buildings over a long period of time. The subjects of the survey were households that were long-term occupants of public rental housing estates that were constructed in the 1960s. Analyses were made of how the occupants lived in the dwellings and records of infill improvements, along with changes in the family structures. In some apartment buildings that were surveyed, an additional living area had been built onto the balcony side, and as a result of having more living space, young couples with children had moved in later. On the other hand, apartment buildings that had not had any additions could be occupied by only elderly households. With households that wanted to continue living in the same place for a long term, despite rental housing restrictions, cases could be seen where infill improvements had been actively carried out on the inside in order to improve the habitability.

This research examines how the apartment units of a housing estate, most of which were equipped with movable partitions and movable storage units, have been transformed by the residents since they ...

A complete enumerative study was made of the repair and improvement work costs of the 1255 general sorting post offices throughout Japan in 2000. This paper analyses the 2000 expenditure figures from both the national enumerative survey and the survey of the five post offices being monitored for twenty years after their completion. The results show that the average annual repair work cost is 665 yen per square metre, and the average annual improvement work cost is 4231 yen per square metre, which total an average annual cost of 4896 yen per square metre. The repair and improvement work cost reaches an accumulated total of around 50 000 yen per square metre 20 years after a building has been completed, and an accumulated total of around 250 000 yen per square metre 50 years after completion. After analysing the relationship between the rebuilding cycle, and rebuilding, repair and improvement costs, by changing the present rebuilding at age 40 to building additions at age 40 and rebuilding at age 60, it bec...

A complete enumerative study was made of the operating and maintenance costs of the 1,255 delivery post offices throughout Japan in 2000, in order to grasp the characteristics of the whole life costs of post office buildings. The operating and maintenance cost of five standard post offices were also monitored for 20 years. This paper demonstrates how the acquired knowledge of the whole life costs is used for the decision making of the facility investment. After analysing the relationship between the rebuilding cycle, and rebuilding, repair and improvement costs, by changing the present rebuilding at age 40 to building additions at age 40 and rebuilding at age 60, it became apparent that a significant reduction in facilities investment costs could be expected.

A complete enumerative survey was made of the repair and improvement work costs of the 1,255 general sorting post offices throughout Japan in 2000. This paper analyses the 2000 expenditure figures from both the national enumerative survey and the survey of the five post offices being monitored for twenty years after their completion. The results show that the average annual repair work cost is 665 yen per square meter, and the average annual improvement work cost is 4,231 yen per square meter, which total an average annual cost of 4,896 yen per square meter. The repair and improvement work cost reaches an accumulated total of around 50,000 yen per square meter 20 years after a building has been completed, and an accumulated total of around 250,000 yen per square meter 50 years after completion. After analyzing the relationship between the rebuilding cycle, and rebuilding, repair and improvement costs, by changing the present rebuilding at age 40 to building additions at age 40 and rebuilding at age 60, it became apparent that we could expect a significant reduction in facilities investment costs.

In the past, the average life of housing in Japan had been around 30 years vs. 77 years in the UK. In the late 1970's, the Japanese government and private sector started research and development projects to design and build longer life housing that is adaptable with time, such as the Kodan Experimental Housing Project (KEP) and the Century Housing Project (CHS). We have been researching the outcomes of those experimental projects to determine whether the attempted adaptability has worked or not over the thirty plus years that people have been living in them. We found that the housing with adaptable infill has been able to adjust to changes in family size and lifestyles in the KEP and CHS projects and have reported on it at several CIB conferences. The Japanese government enacted the Long Life Housing Law in 2009 to extend the life of Japanese housing and increase its adaptability over time. The law's technical guidelines require that continuous efforts be made to improve adaptability to extend the life of housing, and the amount of housing built based on these guidelines has been increasing. In the near future, Japan will have a shortage of construction workers. Therefore, an infill system that can be installed by unskilled labor needs to be developed. We need to compensate for the coming labor shortage in the construction sector by improving its relatively low productivity. We think it is becoming more important to design and construct buildings which require less skilled labor. At the same time, the infill of those buildings needs to be simple like furniture, easy to install on site, and easy to replace by residents and users. The concept of Open Building will play an important role in Japan's future.