Challenging Self-Building

Recently, I have been seeing the term "self-build" more often in housing magazines and other media. Inspired by seeing cottage gardens in the Cotswolds region of the UK where I studied abroad, I built my own home in Nasu 22 years ago through self-building (Photo 1). I was so moved by the British cottage gardens, where the house and garden seem to be integrated, that I studied house building from scratch and decided to challenge myself to a self-build with my wife. The experience of building a house changed my outlook on life, and later, in 2003, I founded a design company called Half Build Home in the same Nasu area.

The motivation for establishing the company was the thought that there was a potential demand from others who, like us, wanted to build their own homes with their own hands through self-building. I commercialized a system to support this at the company. We have worked on about 130 houses so far, and recently I feel it has become much more familiar than in the past, with an increase in DIY programs on TV.

Did you and your wife build your entire home yourselves, Mr. Aoki?

That's right. My wife and I finished everything, including the roof and exterior walls. For the roof, we used a wood called Red Cedar Shake and finished it with wooden shingles. We also created the entire garden ourselves.

That's amazing. How old were you then?

In my 30s. I suppose I could do it because I was young.

Your wife must be happy with a house so rich in greenery. Why did you choose Nasu?

I had wanted to live in the countryside for a long time. I had gone to look at land in Karuizawa and Yatsugatake, but a senior who happened to run a pension in Nasu told me, "There's some good land here," so I decided on the spot.

What kind of people are common among Half Build Home's customers?

Our customers are largely divided into two orientations. One is people who want to build a house with their own hands with the same kind of commitment we had. They visit us because they say other contractors or house makers can't do it. The other is customers who have a small budget but don't want to compromise, so they work hard to build it with their own hands.

Mr. Oka, you are also in the middle of self-building your own home, "Arimasuton-biru," on land along Hijirizaka in Mita. I was surprised to hear that you started building in 2005 and are still continuing to build it with reinforced concrete. What was the trigger for you to build it yourself?

Until I was 30, I lived a life where I worked as a craftsman on construction sites for about half the year, and spent the other half traveling around Japan on a bicycle sketching architecture. On-site, I experienced various trades such as civil engineering, rebar work, formwork carpentry, and scaffolding. It was a life that went relatively as planned, without any major setbacks.

Alongside that, I also attended a private school called the Takayama Architecture School every year, which was started in 1972 by the late Professor Yasuo Kurata, an architect who taught at Hosei University. There, I learned things like the philosophy of an architect.

However, around the time I turned 30, my health broke down, and my spirits sank to the point where I felt I had no choice but to give up on my dream of becoming an architect.

Despite being at such a low point, I got married, and at one point my wife said to me, "Let's build a house for us to live in." If I had been honest, I could have said, "That's a bit impossible for me," but in a moment of madness, I declared, "Leave it to me, I'll build an amazing house for you" (laughs).

That one sentence decided your life, didn't it? (laughs).

That said, at first I didn't know what to build. For the time being, I bought the land along Hijirizaka around 2000, but it was five years later that I started construction.

What were you doing for those five years?

I was constantly worrying about what to build and how. I finally made up my mind when I realized there was no point in worrying any further and decided to trust what I had learned up to that point.

Even so, five years is a long time.

Yes, it is. When I first started building, I was just moving my hands blindly, but gradually the shape began to emerge, and I slowly understood my own way of building. Then, more people started coming to see it, and they began saying things like "This part is great!" about things I hadn't even noticed myself. I've continued building while regaining my confidence in that way, leading to where I am today (Photo 2).

At Shonan Fujisawa Campus (SFC) where I work, we are also moving forward with a project called "Student-Built Campus (SBC)" in which students participate in construction. Since SFC is a suburban campus, it was a long-cherished wish to build accommodation facilities where students could stay while conducting research and education. Therefore, this project was called "Miraisozojuku (Institute for Designing the Future)," and construction plans were moving forward around 2008 with a design by Fumihiko Maki.

However, the Lehman shock occurred just as we were about to decide on a contractor, and the project stalled. The plan started moving again in 2015, when SFC celebrated its 25th anniversary. Around the previous year, the idea came up that if there were no contractors, we should just build it ourselves, and it developed into a project to increase the number of small one-story wooden buildings over about five years. Currently, all seven buildings are completed (Photo 3).

SBC aims to build accommodation facilities while also linking student involvement in design and construction to learning and research. Under the concept of an "unfinished campus," we decided to learn about destroying at the same time as learning about building, and even now, five years after the initial plan, it continues through classes where students make furniture or change the interior. One of the goals is to continue this for 20 or 30 years. I also find it interesting to practice "destroying while building" within the university system.

How have the students been involved?

Mainly in design. While faculty members supported aspects of structure, regulations, and technology, students drew blueprints and made models. On the construction side, we created a scheme where students could participate in the form of part-time work for a construction company so that they would not be liable for defect warranties.

As a part-time worker, how far can they get involved?

At first it was just painting, but we gradually expanded the scope while building the seven structures, and in the end, they were also in charge of installing frame hardware and braces to reinforce the structure.

In our company, the owners themselves handle the interior work by having our staff provide hands-on lectures and support on-site.

If such schemes were to spread more, house building would become more fun, but in Japan, there is also the circumstance that drawing the line between the owner's responsibility and the construction company's responsibility is very difficult. In the case of SBC, if this could be viewed more broadly as student study and done regardless of existing systems and defect liability, the scope of learning would surely expand.

That's true. Changing regulations from the root takes a tremendous amount of effort. The method of involving students as part-time workers was born from the idea of hacking the existing system. In other words, it's an idea to reinterpret and use a certain system for a purpose different from its original one.

It's an idea born from focusing on student learning.

Exactly. From the position of a part-time worker, insurance systems can be applied, and it's a mechanism where the students, the university, and the construction company all benefit.

Under the current Building Standards Act, all floor areas of 10 square meters or more require a building confirmation application, and the rule is that the designer must conduct construction supervision until the completion inspection. I feel this is also becoming a barrier to self-building. For example, why is a building confirmation application, designer construction supervision, and completion inspection necessary to build a small 20-square-meter hut at one's own risk on a large 300-tsubo plot of land in the countryside?

On the other hand, a timber shortage called the "wood shock" is currently occurring worldwide. This is said to be caused by the increased demand for DIY in the US during the stay-at-home period. In other words, in Europe and the US, people are easily building houses, huts, and garages on their own land on holidays, and I think the legal restrictions are quite different from those in Japan.

Nowadays, the number of large home centers in Japan has increased, and materials have become easier to obtain. Detailed information for building structures can also be easily gathered on the internet, and I usually watch a lot of YouTube myself. It's a waste because it's really a great era for self-building.

Compared to when I was building my own home, the amount of information is like night and day. Of course, there is a lot of fake information, so caution is necessary.

I think people who can make or fix the things they use with their own hands like that have a high probability of surviving even in critical situations.

However, current Japanese society has somewhat abandoned half of that. A society without diversity is also a society that is highly likely to decline due to environmental changes. I feel that the fact that laws have become rigid is not unrelated to survival strategy when viewed from a broad perspective.

I truly think so too.

In 2005, when I started building Arimasuton-biru, the structural calculation forgery problem, the so-called Aneha incident, occurred. That triggered very strict legal regulations. Until then, the government had been moving toward entrusting confirmation applications to the private sector, but the awareness of contractors and craftsmen changed significantly after this.

After that incident, the Act on Promotion of Quality Assurance of Housing (Quality Assurance Act) was created. It required construction companies and contractors to provide financial backing, or collateral, to guarantee defects for 10 years.

However, since the Quality Assurance Act is a law based on the premise that construction companies build, self-building is not taken into consideration. Even a small self-build with a construction cost of about 5 million yen is subject to the Quality Assurance Act. Of course, it is a law to protect consumers, but the reality is that it instead restricts people who want to build their own homes casually.

As Mr. Oka says, there are more large home centers now, and it's an era where it's easy to build. Many people can now obtain various information from the internet. Despite that, only the regulations are still determined in a centralized manner. There are too few options for building structures.

By the way, Mr. Oka, why did you try to build in Mita, and with reinforced concrete, which takes time and effort?

I originally liked youth towns like Koenji and Shimokitazawa, so I was resistant to Mita at first. It's a business district, and I felt a high barrier in Keio being nearby. I settled on Mita because there happened to be land that we could somehow afford with our own wallets. If there's an advantage, it's that the Architectural Institute of Japan is nearby, so various acquaintances stop by.

There's no deep reason for choosing reinforced concrete construction either. Reinforced concrete is called "RC," right? When I learned that during my technical college days, Kiyoshiro Imawano's RC Succession was popular (laughs). I was a big fan, and at one point I thought that if I started a company called "RC Sakuseijo" (RC Production Plant) that makes reinforced concrete, I might be able to become friends with Kiyoshiro.

That certainly isn't a deep reason (laughs). But I think there's a big leap between the decision to buy land and build with RC, and trying to do it all yourself.

One reason might be my experience on-site. Working at general contractor and house maker sites, I saw craftsmen doing quite sloppy work in various places. When you see that, you really can't spend your own hard-earned money on them.

Another reason is that I used to be a dancer. In particular, I was dedicated to expressing what I felt on stage through improvisation. I thought this methodology was quite good and wondered if I could do the same with architecture. I thought RC, which allows you to freely change the form while building, was improvisational and the perfect material for me.

Mr. Oka, you are facing your own sensibilities honestly. I feel that even if the shape is vague, if the desire to build isn't at the starting point, self-building won't be interesting.

When you keep building for a long time, you start to doubt the methods you thought were correct until then. If you try a different method as an experiment, it often works out surprisingly well, and you find a new path.

For example, I recently discovered that applying vinyl to the inside of concrete formwork makes the surface smooth. Furthermore, after pouring concrete, the formwork is usually removed within a few days, but if you leave it for two or three weeks, the finish becomes better. Apparently, this is because if you let the concrete rest without exposing it to wind and rain, a glassy substance is generated within the cement. It's very exciting to discover things that aren't even taught in school. That's what I enjoy the most.

What's important is the thought, commitment, and sensibility that you want to make something like this. Without that, if you just gather how-to information, the good aspects of self-building—the handmade feel that professionals can't produce, or the creations born from generous and free ideas—won't emerge. As a result, it ends up being a self-built house that looks like it was made by a poor carpenter.

I think there are many people in the world doing self-building. I have a friend in the architectural field who lives in Hakushu, Yamanashi Prefecture, and he says there are many people around him who move from Tokyo to build houses. But apparently half of them fail.

Why is that?

Apparently, they become unable to do anything halfway through and give up.

As a result of starting from pouring the foundation themselves, it takes too much time, and many people are forced to give up because the exposed timber rots. To prevent that, our company always handles everything from the frame work to the weatherproofing and exterior wall work. we leave the interior work, which doesn't involve the structure or leaks, to the owner.

That means you hand it over in a skeleton state with the walls, pillars, and ceiling completed. In that case, the percentage of people who can see it through to the end increases significantly.

Mr. Oka, when you started building Arimasuton-biru, could you have predicted that it wouldn't be finished even after 16 years?

No, not at all. I told my wife, "It'll be finished in three years" (laughs). However, from around that time, I was also being threatened by self-building masters like architects Osamu Ishiyama and Terunobu Fujimori, who told me, "Your life will change."

A famous French self-built work is the "Palais Idéal du Facteur Cheval," isn't it? It's a building that Ferdinand Cheval, who was a postman, built by diligently piling up stones he picked up. Mr. Oka, did you originally intend to become like Cheval?

I had an admiration for people like Ferdinand Cheval or Simon Rodia, who built the Watts Towers in the US by himself. I felt that Japan would be in trouble if there weren't people who pushed boundaries like that. I never thought I would become one of them myself, though (laughs).

But in reality, I thought I could finish it in a few years. I'm not an amateur like Cheval or Rodia. I'm a first-class architects and building engineers (Ikkyu-Kenchikushi), and I had the pride of having been forged on construction sites.

In our case, we thought we could do it in six months. That was partly because our unemployment insurance would run out if we didn't finish by then, but for some reason, there's an initial optimistic outlook where you convince yourself it can be done in a short time. In reality, it took us ten months.

Ten months is fast!

No, toward the end, my legs, back, and finger joints wouldn't move at all. I felt like I was doing it while crying at the very end. I think it was a challenge I could only pull off because I was young.

Nowadays, half of the customers who come to Half Build Home build using mortgages, but with a loan, there's a constraint where the bank requires completion within about a year. If it's self-funded, it doesn't matter how many years it takes, but for loans, we create a menu that ensures completion within a year.

For example, while estimating the customer's ability, motivation, physical strength, level of family cooperation, and the time they can devote to house building, we try to ensure the house isn't too large, or suggest leaving the interior work to a carpenter if it looks like it will take too long. A large part of our job is supporting them through every step of the process to lead them to completion.

Is the conventional post-and-beam construction method the most common?

It's 2x4 (two-by-four).

With 2x4, you can build without taking too much time. I used to work as a 2x4 carpenter, and I thought the person who came up with this method was a genius. I was struck by what an easy-to-build system it is.

Speaking of systems, what I find most wonderful in Japanese architectural culture is Ise Jingu. The system of Shikinen Sengu, where the shrine buildings are rebuilt every 20 years, is said to have been established during the era of Emperor Tenmu, and I think the person who thought of this system was also a genius.

A 20-year span is just right for passing on traditions and techniques. I feel that if you leave a longer gap, some parts might fail to be transmitted.

I think a model where the physical matter is replaced every 20 years while remaining Ise Jingu as a system is close to a living organism. We humans also completely replace ourselves at the cellular level compared to a year ago. Inside the body, new cells are being created while old ones are being destroyed. Yet, mysteriously, our personality is maintained.

When you look at Shikinen Sengu not just as the shrine buildings but as a single system including the surrounding people involved, the man-made object of architecture starts to seem like a human body.

The opposite of this kind of architecture is the Parthenon in Greece; that temple can be called a model that entrusted the permanence of architecture to the substance of marble. Looking at it through this contrast, I think a certain kind of thinking about sustainability, similar to a living organism, emerges from the act of self-building or building while simultaneously destroying.

I see.

As environmental issues become more serious and sustainability is discussed more severely, I think this biological model might gain reality in the architectural world. Then, legal frameworks might be developed, such as requiring rebuilding every three years, or exempting minor structures from the Housing Quality Assurance Act. I feel that laws will only start to change once we reach that stage.

That's an interesting point. When people participate in construction and come to understand the structure and mechanisms, customers become able to perform their own maintenance. Since they understand why cracks appear in plaster walls, complaints disappear, and they understand that it's natural for wood to warp.

In normal residential construction where the owner does not participate, even a minor defect leads to a complaint. Because of that, some construction companies stop using solid wood or mix adhesives into plaster to prevent even the slightest crack. That's a cat-and-mouse game. I wish more people would get involved in house building so that such instances would decrease.

It's something you don't know until you actually try it, but self-building is a series of discoveries.

I truly think so.

The inside of a construction site is a different world, so it's full of new discoveries every day. Not only do your technical skills improve, but you also get a glimpse into the worldview of craftsmen, and there's so much to learn from that alone. This experience is truly significant.

Yes, there is learning. I've worked on many different sites, but one of the reasons the Arimasuton Building takes so much time is simply because there's a lot of work.

On a normal site, someone else does the work you aren't assigned to. For example, there's an older laborer on site sweeping with a broom, and back when I was a craftsman, I didn't pay much attention to people like that. However, when you're building alone, you have to do even the minor cleaning yourself.

I'm always eating breakfast thinking, "Today I'm going to do this first!" but then I realize, no, that's not it. I'll remember it's Tuesday, so I have to put out the burnable trash first (laughs). Because of those chores, I can't immerse myself in the work 24/7. When you're alone, even these things become a learning experience.

When you participate in a construction site, you deeply understand the hardships of people doing various jobs in society, especially the hardships of those on-site. All our customers say their outlook on life changes, and I truly believe that.

How did your own outlook on life change, Mr. Aoki?

After graduating from university, I worked for a large corporation where everyone around me was also a university graduate. From this world of limited social circles, I suddenly went to Nasu and started dealing with foundation contractors on-site.

Of course, I experienced culture shock at first, but as I became closer to them, I learned from their ways of thinking and living. I began to see things from a completely different perspective than my previous relationships.

Mr. Matsukawa, what do you think when you look at students today?

Currently, the field of architectural design is in a trend of digitalization, but when students design furniture with CAD or other design software, they end up assembling 3D models with boards that are zero millimeters thick or points with zero length.

But in reality, that's impossible. To make a chair, the board has a thickness, and to connect wood, you have to design the joints. Then, when students face the actual object, they find that the joints don't work.

It's obvious when you think about it, but I'm afraid that without experiencing that struggle with physical objects, we'll end up with architects who don't consider weight or tactile sensation. My specialty is digitalization, but watching the students, I think it's equally important to put effort into the DIY world—that is, grappling with physical objects.

Our customers start with installing insulation, then move on to floors, ceilings, and doors, and finally finish with painting, plastering, and masonry; they do it more carefully than a carpenter would.

That makes sense.

When we carefully teach them things like how to put insulation behind outlets or how to avoid gaps, they do a better job than a carpenter. As a result, the insulation performance becomes incredibly good. I don't think you can understand that level of satisfaction unless you've actually done it yourself.

What is the overall cost of the Arimasuton Building? I imagine building for 16 years incurs a fair amount of cost.

I'm borrowing money to build it, but setting aside my labor costs, the material costs are low, so it's an amount I have a good prospect of repaying. I'm not making a giant sculpture, and once it's finished, a life without rent payments will begin, so the balance sheet works out.

Mr. Aoki mentioned loans earlier, but even if you try to challenge yourself with self-building on your own now, the system is set up so that if you receive the full amount of a mortgage at the start, you have to finish within a year. That doesn't accommodate cases like the Arimasuton Building that take 10 or 20 years.

So, for example, I'd like to see loan formats diversify, such as a system where you borrow 10 million yen in increments of 1 million per year over 10 years and use it each year. This is because in today's uncertain society, adapting agilely to ever-changing situations is important as a survival strategy. The self-building method of taking time to build and destroy provides hints for surviving modern society.

I don't know about a 10-year span, but the changes over 20 or 30 years are certainly huge. In fact, many buildings from the bubble era are gone without a trace, and right now, a super-high-rise office building is under construction behind the Arimasuton Building, but everyone must know that demand for office buildings will decrease in the post-COVID society. Even so, they try to finish that building. We should rethink this sense of rigidity.

Large-scale redevelopments are particularly high-risk. From now on, it will be important to maintain a state where trial and error is easy.

Customers always ask how much cheaper it is with self-building, and for 30 tsubo (approx. 100 sq meters), it's about 3 million yen. However, whether that amount is a gain for the customer isn't known until everything is actually finished.

This is because some people end up regretting it, saying, "I shouldn't have done it." Naturally, those people don't feel like they've successfully saved costs.

To put it a bit harshly, self-building is difficult for people who lack perseverance, grit, and planning skills. People who can push themselves even on Sundays and work strictly from 8 AM to 7 PM are the ones who finish in a year. Woodworking skills aren't actually that important.

Are there no people who can push through on excitement alone?

In interior work, the big jobs requiring physical strength come first. That includes things like installing insulation and putting up ceiling and floor materials, and if you can break through that in three months, you can make it to the end. Conversely, if it takes too long, motivation drops sharply. This is the worst thing. Our staff encourages and helps them, but it's quite difficult.

Grappling with physical objects is purely fun work, but it's not simple enough to get through on that alone.

The insulation, ceiling, and floor processes are monotonous, after all.

Perhaps people like you, Mr. Aoki, who take on the challenge with a wonderful ideal in mind, are the ones who can work hard until the end.

Yes. Especially if a couple is in step with each other, they'll usually be fine. The satisfaction with the finished product is also high.

The act of making itself is interesting, so if you can enjoy that, you can see it through, and it leads to the next thing. I'm also doing it with excitement every day.

Regarding the act of "making," I think human prosperity has always been about continuing to make things with our hands. I think we produced food, wove clothes, and built houses because, in the end, things were scarce. However, entering the modern era, as soon as we became flooded with things, people stopped making them. To put it extremely, in this day and age, everyone is only touching their smartphones, right?

To me, it seems like humanity is at a tremendous turning point. We must not stop making things in order to survive, yet things are overflowing. If that's the case, I think we have to invent a "making" that fits the current era.

That's philosophical. It's an interesting topic.

So I'm suggesting we think about "new making." When I say that, most people go toward art, but it doesn't have to be that. Because the only ones who can truly do art are the champions of craftsmanship. Artists are the type of people for whom "making" wells up from within themselves.

Until now, I hadn't been able to successfully link my specialty of architectural digitalization with the DIY world of grappling with physical objects, but recently I've finally seen a clue to connect them.

Humans coexist with various substances and fungi to maintain being human, but as I mentioned with the example of Ise Jingu, there is a way of perceiving architecture as a living organism. Taking inspiration from this, I am now creating a system to grow architecture like an ecosystem using computer programs. To materialize it from information into physical space, human hands are needed as part of the system. This is where the connection with the DIY-like world is born.

Architecture reaches thermodynamic death as entropy increases the moment people stop making it. I want to create "living architecture" by keeping a complex system of humans and machines running. That is "new making" for me.

Regarding "new making," I think it's very good for making things to be related to food, clothing, and shelter. For example, trying to grow vegetables in a garden, fixing a broken part of the house yourself, or having to sew a tear in your clothes—food, clothing, and shelter are easy to start with because they provide a trigger.

Moreover, we are in an era where you can share with many people that you made this kind of dish and it was delicious. Not everyone needs to build a house from scratch, but everyone should do more things related to food, clothing, and shelter themselves.

It would be great if everyone started enjoying making things more.