Sky Garden House / Keiji Ashizawa Design

© Daici Ano

Architects: Keiji Ashizawa Design / Keiji Ashizawa, Mriko Irie
Location: Tokyo,
Structural Engineer: ÅFASA Akira Suzuki
Landscape Design: GLAC Corporation
Furniture Design: DRILL DESIGN / Keiji Ashizawa
Building Construction: Heisei Construction Co., Ltd.
Project Year: 2010
Photographs: Daici Ano

Sky Garden House is a two-family residence in central Tokyo. The main goal in design was to create an environment where two families can interact freely and frequently, while giving each family a high level of privacy from each other as well as from outside. The peculiar nature of the location and limitations imposed by the building codes (in particular, the building-to-land ratio) presented considerable challenges in meeting this goal.

© Daici Ano

The house, where Clients and their two children occupy the first two floors and their parents live on the third floor, is built on a steep incline, with about 5 meters in height difference between the low and high points of the land, rendering part of the first floor effectively underground.


The building-to-land ratio required that maximum use of the available space be made to secure open, comfortable living space for two families. We and Clients sought to address these challenges through a series of extended discussions, in a process not unlike trying to piece together a complex puzzle.

© Daici Ano

In the end, we decided on three design features in meeting these challenges. First, we designed a lightwell and had each room face it. This had two benefits. One was that this would ensure that each room on the first three floors would receive good amount of sunlight. The other was that it would create an open and spacious feel to the house while allowing for privacy from outside environs.

Floor Plan
Cite: "Sky Garden House / Keiji Ashizawa Design" 16 Oct 2011. ArchDaily. Accessed 22 May 2015. <>