The site is located in a residential district, which is easily accessible from a principal road. It is a so-called “flagpole-shaped site”, meaning that the rectangular site is located at some distance from the public road and linked to it by a long and narrow path. The site is surrounded by two-story and three- story buildings on the four sides. The client requested an indoor garage so that he can enjoy looking at his beloved car from living room and also an inclined roof with solar panels.
We decided to build a one-story wood house because of two reasons; the floor area requested by the client was relatively small in comparison to the site area; and the allowable bearing capacity of the ground soil was low because the land had been used for farming and therefore the building had to be light with a relatively large building area. Our biggest challenge was to provide natural light inside the one-story house and also to ensure enough solar energy on the roof, within the congested condition surrounded by two-story and three-story buildings. It was also essential to design the house in harmony with the surrounding townscape. Therefore the roof design became the key to our proposal, and we start our design from there.
The roof is composed of a combination of the traditional Japanese-style inclined roof and the flat roof, which is a typical modern architecture style. The size of the pitched roof was decided by the numbers of solar panels required to generate sufficient energy to serve this house, and it was installed at the center of the site to avoid shadows of the surrounding buildings. The ceiling follows the inclination of the roof. The roof structure is raised above the equally spaced columns, which are built on top of the flat-roofed volumes on the east and the west sides. From the interior space, the residents can enjoy the unobstructed view of the sky through the openings between the inclined roof and the flat roof on both sides. Seen from outside, the inclined roof leans on the simple and horizontal volumes on both sides, and each of the three areas is allocated for different functions of the house.