House T | SUPPOSE DESIGN OFFICE Co., Ltd.

A cave-like shadow and a warm home that has been reconsidered to the extent of the design

Building a House in Tokyo

I never thought that we would be building our house in Tokyo.
When my son was about to turn four years old, my wife asked me, “What about our house? I asked.
We had bought a condominium in Hiroshima a few years before and had gotten used to living in a rented house in Tokyo.
Land in Tokyo is expensive, and I thought I would never own a house in Tokyo, nor did I imagine staying in Tokyo for a long time, but with a word from my wife, the reality of building a house in Tokyo suddenly came to me one day.

After that day, I began to spend my days and nights searching for sites on the Internet.
I have designed more than 150 houses so far, but being on the actual builder’s side is a precious experience, so I decided to write about how the idea of building a home became a reality, leaving a little archive on a paid blog called “note.”
You can’t shake what you don’t have, and when it comes to finding a site in this high land price area, where it is generally said that about five times the household income is the limit for loans, they naturally created the path of building a small house on a remote site. Considering the need to travel for work, it was hard to imagine living in the suburbs, and if you were to go to Tokyo, you would have to pay over 3 million yen per tsubo for a site, and even 20 tsubos site would cost around 60 million yen.
Considering the soaring construction costs, a three-story house with a floor area of 12 tsubos at a building-to-land ratio of 60% would cost 36 tsubos.
Assuming 1.5 million yen per tsubo, the construction cost would be 54 million yen, and considering the fees and taxes for income from real estate, it was easy to imagine that the price would exceed 100 million yen even for a small site.
Even if we assume 120 million yen, we would have to pay 380,000 yen per month for the next 30 years, even if the down payment is aside and the interest rate is 1% for a 30-year loan. Considering this reality, I was 44 years old at the time and would have to keep working until I was 74.
Even if I took out a loan, I would keep myself busy, but there is no guarantee that this will continue for the next 30 years. After becoming the owner of the house, I realized the reality that everyone is getting their own home with such anxiety.

Even so, I thought that the price per tsubo would be lower if the site were in bad condition, such as a deformed site, so I continued to search the Internet every night using keywords such as “narrow, deformed site, sloping site.”
Since running my own real estate company called Spectacular Real Estate, I repeatedly searched for sites in Tokyo for less than 50 million yen on the real estate agent’s website Raines. Still, it was challenging to find a place with the conditions I wanted, and even if I did, I could not imagine living there for a long time.

One day, I decided to look for a larger site, leaving my financial situation aside for the time being.
Then, I found a fair amount of information about sites of about 40 to 50 tsubos.
I gradually realized that there might be a range of difficult sizes to reach in a sense where developers of condominiums, etc., cannot cram as many households as possible. In contrast, the price range is such that you need a certain amount of income to buy a house.
Until then, I had known the word “yield,” but I had only been aware that about 5% would be acceptable in Tokyo without knowing what it specifically meant. For the first time, I learned how to calculate the yield and decided to make an overall plan as a business model for both renting and selling.

Since the price per tsubo (square meter) was higher in commercial areas, I looked for sites in residential areas, ordered survey maps, made rough plans, and repeated trials with many places to see if I could make a reasonable repayment plan for the combination of home and rental.

For a site of about 50 tsubos in a residential zoning district in the center of Tokyo, the cost per tsubo was about 4 million yen, and the site cost 200 million yen. With a building-to-land ratio of 60% and a floor-area ratio of 160% (assuming a 4-meter front road), that would be 80 tsubos. In other words, a three-story building would have the first floor of 30 tsubo / 100 m², a second floor and the third floor of 20 tsubos / 66 m² of interior space, and a terrace of 33 m². If we assume that the interest rate is 1% for a 30-year repayment, the monthly rent would be 964,000 yen. Thirty tsubos / 100m² is considered a home, and the remaining 50 tsubos / 164m² is a rental. The rent would be 1,000,000 yen, which is about 20,000 yen per tsubo in the city center. Even if the amount of money fluctuates depending on the number of floors, considering the home part’s cost burden, I knew that I could secure a certain amount of space in Tokyo with a reasonable payment plan.
In addition, even if I were unable to work, I would avoid difficulties in paying the loan by renting my house.
With the above conditions in mind, I narrowed my search to a site with a floor area of around 50 tsubos and favorable road diagonals and shade. I spent my days like a muscle train, searching for a site in a specific area, obtaining a survey map, making a plan, and confirming the business income and expenditure.

One day, I received a phone call from a friend in the real estate industry concerned about my search for a site, and he sent me a picture of a place that looked good.
He sent me a picture of it, saying that there was information about a sale site that looked good. There was a sign on a colored cone, the same kind of real estate information often posted on telegraph poles.
I was hesitant to call the number because I imagined a story like the one on TV, where if you call this kind of sign, there is a scary person on the other end of the phone, and you have to force yourself to buy the house. So I made the call. Then, although it was just my impression over the phone, a person with a good impression answered the phone and politely told me about the real estate information.
Unfortunately, the information was not what I was looking for, but since the real estate company was very knowledgeable about information in Tokyo, I decided to meet with them later to give them specific knowledge and have them look for a site for me.
A few weeks later, I received a call from the company saying, “There is a site for sale in a certain area, so please take a look.” I immediately went to the site to check out the surrounding area and then worked overnight to plan. I was convinced that I could design the architecture as close as possible to the imaginary scenario that I had tried repeatedly. The next day, we put in an application to acquire land for the first time in our lives, and our house building in Tokyo began.

As a detailed plan, we decided to build a basement floor directly accessible from the road on a stepped site with a dug-in garage, a second floor that creates a sense of openness even though it is closed off by securing a high floor, and the third floor with a maximally raised view.
I designed the floor plan to be variable in the future, with the perimeter made of concrete and the interior made of wood. I studied the building’s proportions, and I made the plan and cross-sectional plans hoping that anyone could live in the house.

Although it is not the opposite of the houses I have designed in the past, I narrowed down the number of openings to create darkness rather than lightness and created a light gradation.
To create a sense of presence rather than thinness, create thickness rather than thinness, increase the number of lines rather than decrease them, and create shadows.
Coarse materials are handled delicately, and the space is not inorganic but organic, with materials asserting themselves.
No air-conditioning is used; cold water is passed through louvered pipes on the ceiling to cool the room in summer, and warm water is given under the floor to warm the room by the fireplace in winter.

Space was like the townhouse’s original landscape where I spent my childhood, looking out from a dark room at the courtyard in a long, narrow space like an eel’s bed. In summer, water is sprinkled on the floor to create a breeze to cool the air due to the atmospheric pressure change. We chopped and burned wood to boil water for the bath. It was as if they had brought the past lifestyle, which made use of things found in nature, into the present.

The spatial experience, where the pillars, beams, and sand walls’ texture brought warmth to the dark and quiet space, was recreated as warm concrete by making the concrete rough but delicate. The negative memories of an inconvenient and difficult childhood to live in had passed over time, and I found myself instead of pursuing the spatial landscape of those days somewhere else.

My main concern was how to build a house rather than how to create exemplary architecture, but it was also an experience that made me realize how much I think about the act of designing in the sense of keeping within a budget. Still, I have not designed with an understanding of the economic environment of the client.
Architects focus their energy on creating buildings within the budget set by the client.
However, how often have we imagined the economy that lies beyond that?
Whether it is a private client or a commercial project, if we as architects understood the economic system behind the project, we would advise the client on the proposed budget and be more committed to the project.
If the design scope includes both before and after the building’s construction, then the client will probably commission an architect who will consider this.
It is precise because architectural projects require large sums of money that may be necessary for us to design a balance between economics and architecture.
We need to create exemplary architecture, and if people feel sympathy for it, they will ask us to work on it.
That is what I sincerely want to do myself.
At the same time, through this project of building my own house, I understand that architecture is created in a balance between the builder’s hopes for a new home and economic anxiety.
I want to reconsider this relationship between economic activities and architecture, which I have somehow separated, and continue to think about good architecture.

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.
Through many hesitations and challenges, the memories of the past and the thoughts of the present blended, and my own house was completed as if it had always stood there.
(Makoto Tanijiri)

【HOUSE T】

所在地：東京都
用途：併用住宅
クライアント：谷尻 誠
竣工：2020年

設計：SUPPOSE DESIGN OFFICE
担当：谷尻 誠、濱谷明博
構造設計：堀江建築設計事務所
家具：E&Y＋SET UP＋TIMBER CREW
設備設計：島津設備設計事務所
照明設計：Filaments＋ModuleX
植栽：SOLSO
施工協力：賀茂クラフト＋SET UP
施工：21世紀工務店

撮影：矢野紀行

工事種別：新築
構造：RC造
規模：地上2階 地下1階
敷地面積：175.60m²
建築面積：115.20m²
延床面積：285.36m²
設計期間：2018.05-2019.02
施工期間：2019.02-2020.08

【HOUSE T】

Location: Tokyo, Japan
Principal use: Residential
Client: Makoto Tanijiri
Completion: 2020

Architects: SUPPOSE DESIGN OFFICE
Design team: Makoto Tanijiri, Akihiro Hamatani
Structure engineer: Horie Architect Office
Furniture: E&Y + SET UP + TIMBER CREW
Facility design: Shimazu Design Office
Lighting design: Filaments + ModuleX
Planting: SOLSO
Construction cooperation: Kamo craft + SET UP
Contractor: Twenty-first century constructions

Photographs: Toshiyuki Yano

Construction type: New building
Main structure: Reinforced Concrete construction
Building scale: 2 stories and 1 below
Site area: 175.60m²
Building area: 115.20m²
Total floor area: 285.36m²
Design term: 2018.05-2019.02
Construction term: 2019.02-2020.08