Grass Cave House: Makiko Tsukada


The site is surrounded by gentle hills, and a green area unfolds in front of the narrow-centered “V” shaped site. The architects attempted to adjust the distance to cities, as well as that to the natural environment, by utilizing the unique characteristics of the site, and three-dimensionally integrating the green area.

Specifically, the outline of the building was determined to follow the shape of the site. Two floating lawns were planned in a way such that they appear to be continuous with the green area in front. The lawn on the roof of the garage slopes down towards the living room, while directing a line of sight from the interior to trees in the park. Another lawn is made on the roof of the living space. It slopes down towards the street side, creating a rich green scenery along with the surrounding trees. The floating roofs have a hat-like function that work as air conditioners to absorb solar radiation during summer, and as insulation to maintain the interior thermal environment during winter.

The interior space is a large wooden open space with a hollow core at the center. By manipulating the natural light, the distance to the street and the height difference with the street, the space becomes more private towards the back of the house. The central core directs natural light to the first-floor bathroom and its surroundings, while functioning as access to the roof and as a ventilation pipe. In addition, since it structurally bears a large portion of seismic forces, only 50mm thin pipes were required for pillars to support the garage roof with a floating lawn.
This building, which resembles an urbanized rich, green cave, maintains adequate distance from cities while enabling enjoyment of a fresh relationship with city or natural environments through the horizontal and vertical hollows where light enters.

Grass Cave House, Yokohama-shi, Kanagawa
Program: single-family house
Architects: Makiko Tsukada Architects
Structural Engineer: Taizen Nieda and Mitsuyoshi Yoshida
Area: 97,18 sqm
Completion: November 2013


CUBO Design Architect: Cnest


The house is located on a site which can be called a cliff with a maximum elevation difference of 14m and a maximum slope angle of about 70 degrees.
The main features of this site are the views of the sea horizon and rich greenery. The house was planned with consideration of maximizing the utilization of its appeal.

A plan was sought to leave the trees and to create a scenery in which the building blends in. An intuitively germinated image was that of a floating birdhouse with a pointy delta-shaped roof, hanging from a big tree.
As a result, the birdhouse was fixed as if hooked on a block of RC, which was embedded into the ground. The cantilever with a 4m x 13m flat surface, which supports the floating birdhouse, is supported by an RC slab and narrow steel-frame branches.

The way of letting natural light into the interior space allows one to feel the purity of the sunlight, as well as intensifies the beauty of the shadows, which is at the extreme opposite of the light. Walls are arranged to dramatically invite the strong light. A gradation of shading, which is visualized by trimming and manipulating light, causes retinal shrinkage as well as reminds us of the traditional Japanese appreciation of “shadow” parts.

Cnest, Oiso-cho, Kanagawa, Japan
Program: single-family house
Architect: Hitoshi Saruta / CUBO design architect
Structural Engineer: Kenji Nawa (Nawaken-gym)
Area: 338 smq
Completion: September 2013