Yotsuya Tenera | Key Operation Inc/Architects

Situated in a residential district of Tokyo, the three-storey Yotsuya Tenera building occupies a curved site and complies with a number of onerous planning constraints, such as having to build away from boundaries of the site, rights to light and evacuation requirements. While meeting these demands, the architects have succeeded in creating a building of coherence and complexity, with 12 distinct types of apartment accessed from two day-lit and naturally ventilated stairs that eliminate the need for any corridors. The communal stair encourages interaction between residents without compromising privacy. This housing complex consists of 9 one-room units measuring approximately 20m2 and 3 units measuring approximately 30m2. The L-shaped design of the building as a whole secures an open space between the entryway and street, while two tree-shaped voids inside the building allow for a compact arrangement of balconies and walkways between units. The voids provide ventilation because they are oriented towards gaps in the densely-developed residential neighborhood surrounding the building; the chimney effect produced by the tall, tree-shaped voides further enhances air circulation. Light also pours in through the top of the voids. The units have a diverse range of floor plans, including I, L, C, T, and other shapes that wrap around the voids. Standout features of the exterior include concrete poured in larch plywood formwork and hot-dip galvanized metal window frames.