R-Torso-C is a minimalist residence located in Tokyo, Japan, designed by Atelier Tekuto. A house built using a new type of environmentally friendly concrete called SHIRASU concrete. SHIRASU is the deposit of pyroclastic flow of volcanic ash found widely in Kagoshima Prefecture. The external form is the result of a process of pruning off the corners from a regular rectangular volume at an angle facing the sky.
“We want to see exposed concrete finish inside and out. A distinctive piece of architecture that is at the same time environmentally conscious.” These were the initial request of the clients. With those words as a starting point, the architects conducted various studies and researches and the house saw its completion after two and a half years. – Atelier Tekuto
Atelier Tekuto have noticed that ancient Roman concrete used in the Pantheon in Italy, contained volcanic ashes. They have decided to use SHIRASU, the deposit of pyroclastic flow of volcanic ash found in Kagoshima Prefecture, located in the southern part of Japanese Islands.
Although the amount of deposits are estimated to be as much as 75 billion cubic meters, it has not been used as a concrete material for architecture, as it doesn’t meet the criteria of Japanese architectural regulations. On the other hand, Japan is lacking in the fine aggregate used for the manufacture of concrete. The good river sand is getting scarce and has been replaced by the gravel scraped from the bottom of ocean. However most of the local governments have banned the collection from the sea concerning the impact to the environment. Atelier Tekuto worked with University of Tokyo and private enterprises to utilize SHIRASU instead of sand, and performed various experiments and verification almost for two years.
“Environmentally friendly SHIRASU concrete” replaces over 60% of sand with SHIRASU, and is anticipated to give concrete humidity control and deodorizing effects. The fine granularity of SHIRASU provides high density to the concrete and protects the concrete from neutralization, and the strength and durability is expected to increase over a period of time for its pozzolanic reaction. In addition, portland blast furnace slag cement type B is used to contribute to the low-carbon societies, and using the limestone macadam and limestone sand enabled not only to control the drying shrinkage cracking but also to recycle 100% as cement raw material at demolition.
As it’s being self-consolidating concrete, it reduces the noise, vibration and energy at the construction site. The world’s first architecture, R torso C was built using environmentally friendly concrete, as well as incorporating a sectional thermal circulation system.
“I spend a lot of time developing new materials from what other people consider to be ‘waste.’ I’m like a garbage man. If I find materials that are not commonly used or have been discarded, then I get really excited. If I can’t find the materials that go along with the structure, then I invent a new one. For example, I was unhappy with the cement used for homes in Japan, so I worked with Tokyo University to develop a new type. Our recyclable Shirasu Cement is made from volcanic ash deposits.” – Atelier Tekuto
This house is located in the center of Tokyo, on a site area of mere 66㎡. The clients are a married couple both working in the field of chemistry, sharing a passion for architecture and art. “We want to see exposed concrete finish inside and out. A distinctive piece of architecture that is at the same time environmentally conscious.” These were the initial request of the clients. With those words as a starting point, we conducted various studies and researches and the house saw its completion after two and a half years.
The approach to utilize natural materials and the natural environment:
The way of building architecture respectfully towards nature and the environment in high density residential districts in Tokyo is to build towards the “sky”. It is the only direction with a true feeling of the vastness of nature. To form a strong connection with the sky, the corner of a rectangular building was pruned away at an angle. This action, cutting away the internal volume, paradoxically creates a sense of spaciousness in the continuous four story space inside. To secure a comfortable interior climate, a “thermal circulation system” was incorporated in collaboration with an environmental engineer.
Development of environment friendly SHIRASU concrete:
We developed a 100% recyclable concrete which, instead of sand, contains SHIRASU, the deposit of pyroclastic flow of volcanic ash which is found in the Southern parts of Japan in abundance. The advantage of this concrete is its strength and durability that increases to grow over a long period of time because of the pozzolanic reaction of SHIRASU. Also its density, which comes from the fine granularity of SHIRASU, protects the concrete from neutralization. SHIRASU also contains micro closed-cells which gives the concrete humidity control and deodorizing qualities. This development and use of SHIRASU concrete can be a huge asset to those areas where SHIRASU can be excavated.
Transition from the planimetric congnition to the cross-sectional cogitation:
For architecture on a small site, sectional and volumetric design becomes very important. A high level sound insulated audio visual room in the basement, and a spacious gallery and a Japanese room is placed on the first floor. Functionality was prioritized on the second floor with a living room, dining room, kitchen and bathroom. The living room is a very small space, but a 5m high ceiling and a large oblique triangular window, drawing in an abundance of external light, results in a cognition of spaciousness that is far greater than the reality. The final design of this space was derived through a vast number of three-dimensional models.
Project name: R-Torso-C
Location: Shibuya, Tokyo, Japan
- Type By Characteristic: Japanese House, Tower House
- Type By Site: City / Town House
- Type By Size: Small House – (51 sqm – 200 sqm)
- Type By Materials: Concrete House
Construction: Reinforced concrete （frame structure wall with seismic resistance）
Floor count: 4 – B1F-3F
Site area: 66.67 sqm
Building area: 31.21 sqm
Total floor area: 103.74 sqm
Completion Year: April 2015
Client / Owner / Developer: Private
- Atelier Tekuto – 4 Chome-1-20 Jingumae, Shibuya, Tokyo 150-0001, Japan
- Architectural Design: YAMASITA, Yasuhiro + MIZUKAMI, Kenji + TOMOYOSE, Atsushi/ Atelier Tekuto
- Constructional design: SATO, Jun + INOUE, Kenichi / Jun Sato Structural Engineers
- Facility design: YAMADA, Hiroyuki / yamada machinery office
- Cooperative university: NOGUCHI, Takafumi / Tokyo University
- Construction management: MATSUOKA, Shigeki + NAKADE, Shuichi + KITAOKA, Tsubasa / Home Builder