House T by Suppose Design Office is a "cave-like" concrete house in downtown Tokyo

Architect Tanijiri Makoto of Japanese studio Suppose Design Office has created a monolithic concrete home for himself and his family in Tokyo, featuring dark living spaces that open onto a sheltered terrace.

Suppose Design Office has so far created more than 150 houses, but its founder never believed he would be able to build one for himself due to the cost of land in central Tokyo.

The exterior of a stepped concrete house in Japan
The monolithic house occupies a small site in Tokyo

Makoto was living in rented accommodation in Tokyo when he decided to start looking for an affordable plot in the city on which to build his House T.

The price of land in the Japanese capital is prohibitively expensive for most residential buyers, so Makoto originally searched for sites that were less desirable due to their small size, awkward shape or challenging topography.

The concrete facade of a Japanese house
It is intended to evoke a cave

Recognising the value in slightly larger sites that were still too small for commercial housebuilding, the architect devised a plan to build a three-storey incorporating two floors of commercial space that could be rented out.

Eventually, a suitable site in the Shibuya area became available and Makoto designed a building in with his home on the first floor between two floors intended for commercial use.

A hidden concrete-walled courtyard in Japan
Concrete walls were chosen for privacy

The building's layout and appearance are designed to be versatile so to ensure all of the spaces can be adapted to the requirements of potential future occupants.

"I designed the floor plan to be variable in the future, with the perimeter made of concrete and the interior made of wood," Makoto explained.

"I studied the building's proportions, and I made the plan and cross-sectional plans hoping that anyone could live in the house."

The dark concrete interiors of Japanese kitchen
Openings are limited to create dark interiors

From the outside, the building appears as a solid mass of stacked concrete volumes.

A void at street level provides a parking space and shelters the entrance to a showroom space currently rented by a kitchen appliances firm.

Plants that tumble down from terraces on the uppers floors introduce a natural element to the facade. On one side, stairs provide access to the living spaces and a self-contained unit with a large roof terrace that currently hosts a restaurant.

The dark concrete interiors of Japanese kitchen
The home has a large open-plan kitchen and lounge

The need for privacy within the home prompted Makoto to surround it with thick concrete walls. To bring warmth and tactility to the interior, the concrete surfaces are textured and complemented by natural materials and finishes.

According to the architect, the house was informed by the beauty of nature and by the townhouse he grew up in, which featured a dark room looking onto a long, narrow courtyard.

"While maintaining the sensibility of thinking back to the past, I have made full use of engineering that is possible only in the modern age and have transformed a natural environment like a cave into architecture," he said.

A dark timber-lined bedroom
Timber lines the master suite

Openings on the dwelling level are limited to create darkness and intimacy, with a terrace lining one side of the living area providing the main connection to the outdoors.

The entrance hall leads to an open-plan lounge, kitchen and dining space featuring double-height ceilings that allow for a mezzanine level.

A concrete restaurant interior in Japan
A restaurant is among its commercial spaces

A timber-lined box flanking the living area contains the master suite, with its black-tiled bathroom and walk-in closet.

The bedroom features built-in bookshelves and a wooden ceiling that provides a warm complement to the concrete walls.

A Japanese restaurant's concrete roof terrace
The restaurant has a roof terrace

The same palette of robust and raw materials is used throughout the commercial spaces, which could be incorporated into the home in the future or used to continue generating income.

The use of raw concrete is familiar to Makoto, who previously applied a palette of concrete, steel and reclaimed wood when creating the interior for Suppose Design Office's Tokyo studio.

The studio's other residential projects include a house in Fukuoka that slopes down towards the edge of a reservoir, and a home in Anjo featuring a shingle-clad roof that extends out to shelter parts of its garden.

Photography is by Toshiyuki Yano, video is by Toha.

More images and plans

Ground floor plan for House T by Suppose Design Office
Ground floor plan
A section of House T by Suppose Design Office
Section
Section for House T by Suppose Design Office
Section
The living room of House T by Suppose Design Office
The living room of House T by Suppose Design Office
The concrete interiors of a Japanese house
A concrete showroom in Japan
A concrete showroom in Japan
A dark bathroom interior
A dark living room in a Japanese house
A dark living and dining room in a Japanese house
A concrete kitchen in a Japanese house
The exterior of a stepped concrete house in Japan
The exterior of a stepped concrete house in Japan
A concrete facade of a Japanese house
A concrete facade of a Japanese house
A concrete facade of a Japanese house
The concrete interiors of House T in Japan
The concrete interiors of House T by Suppose Design Office
A hidden concrete courtyard of a Japanese house