A new build house for a family of young couples and four children was requested at a site located in residential Setagaya Ward, Tokyo. Most of the neighbouring houses were built on top of levelled land formed by enormous concrete walls to accommodate the hilly terrain. However, at this specified site, no preparation for construction had been carried out. Therefore, the earth itself with a rough slope – a height difference of 3.5m – was available.
▼项目概览，overall view of the project © Masaki Hamada (kkpo)
Several small areas were dug out to make the most of the terrain’s nature. Height differences in the ground level emerged by these digs, and various retaining walls to suit each level were designed. Then, “five small retaining walls” that merge nature and artefact appeared on site. The shape of each retaining wall differs, however, all follow flat structure reinforced by L or T shaped ribs and support the earth load with its thickness, which is set as thin as possible. The thinness of the wall was an attempt to acknowledge the retaining wall – construction material – as an essential part of human living space, and implement this wall in the interior of the house even with its geothermal feature. As a vestige of the earth and architecture’s struggle for their coexistence, this complex border appeared between them should be able to offer vibrant moments in life at this living space.
▼住宅入口，entrance of the project © Masaki Hamada (kkpo)
▼空间轴测图，axonometric drawing © Kiyoaki Takeda Architects
The architecture is stacked on top of this structure, tracing the earth shape by the foundation and retaining walls, and constructed with two layers, which are RC and timber. A space produced by the lower RC structure is basically the underfloor space but turned into an interior. By also using them as living area, together with the space of the timber structure, the building offers one large atrium that accommodates various skip floors with different environments.
▼中庭空间，the atrium space © Masaki Hamada (kkpo)
the upper and lower two-story structures are made of
wood and reinforced concrete respectively © Masaki Hamada (kkpo)
look up at the upper wooden structure © Masaki Hamada (kkpo)
The retaining walls bring stable geothermal heat to the interior, considering the soil behind them as a continuous layer of its own, however, purposefully, the depth of each retaining wall was varied (buried, half-way under the ground, etc.) to make the environment uneven. The timber structure provides an open frame that exposes the beams in the atrium, offering an option to increase the floor space in the future. The diverse environment and structure from each floor level are blended into one living area. Residents would first feel the differences in each space, and then they can explore their own way to manipulate and design their own life within this environment.
▼上下两层空间概览，overview of the upper and lower two levels of space © Masaki Hamada (kkpo)
▼上层木结构空间概览，overview of the space of the upper timber structure © Masaki Hamada (kkpo)
▼开放式厨房区域，open kitchen area © Masaki Hamada (kkpo)
▼挡土墙建造过程，construction process of retaining walls © Masaki Hamada (kkpo)
For this house, I aimed for an architecture that is filled with the life force rooting the earth itself.
I want to bring back the tactile sensation of living in a “place.” It cannot be achieved by just applying soil to the floor. I believe that this sensation can be accomplished only when we, as human beings, are supported and enveloped by the structure of the earth, emerged from the contrast between nature and artefact.
▼总平面图，site plan © Kiyoaki Takeda Architects
residential spaces and retaining walls are divided into planks © Kiyoaki Takeda Architects
Project location: Setagaya, Tokyo, Japan
Completion Year: April 2020
Architect: Kiyoaki Takeda, Miyuki Sakuyama
Structural enjineer: Minoru Fujita Furniture Designer: Hideo Minamikawa / SIGN CRAFT
Translator of concept text: Mami Sayo
Photo credits: : Masaki Hamada (kkpo)