The Tokyo architect takes us behind the scenes of the Tamedia headquarters in Zurich, a modern mid rise employing ancient Japanese joinery construction.

Having explored material in every format – from his cardboard tube emergency shelters to his Centre Pompidou-Metz, with its glulam timber roof – the Tokyo architect and his firm now turns their attention to miyadaiku and sukiya-daiku, the Japanese carpentry techniques of tea houses and temples, which use no nails, screws or other hardware. This sophisticated joinery is the main feature of the 10,120-square-metre Zurich head-quarters of Tamedia, a major publisher of newspapers, magazines and online media. Azure contributor Mimi Zeiger spoke with Ban about what makes this style of wood construction both innovative and sustainable.

What was your inspiration for working with timber joinery on the Tamedia building?
There was no inspiration, just a culmination of my experience in construction. I have been designing different timber structures for a while. My first experiment was a building in Northern Japan – Tazawako Station in Akita Prefecture.

But if you use steel joints, you don’t take advantage of the timber itself. I like any material – concrete, steel, paper — but wood has its own limitations. With steel, you can do anything. You can weld it and make it into any shape. But it is interesting to take advantage of limitations. Wood is a natural material, so you have to understand its nature. It is weaker than steel. You have to take advantage of the weakness.

Wood is a beautiful material; it gives off a warm feeling. With Tamedia, we used spruce. It’s not a hard timber. It’s economical and easy to work with. And it’s very popular in Switzerland, probably the most common timber material in the region.

You are known for innovative building materials. Have you experimented with timber construction at this scale before?
It depends on what you call scale. The roof over the Centre Pompidou art museum in Metz, France, is bigger. The scale is not so important. Even if this were a two-storey building, it is no different than a seven-storey building. Because this is a type of invention, the scale is less important. I can make a much bigger building with the same system. With Tamedia, the scale came from the site and the client. If the site were different, the structure could be bigger or smaller, but the joinery would be the same.

This is your first building in Switzerland. Does working in Zurich differ from working in Tokyo or other places around the world? Did the Swiss authorities ever question your detailing?
With the exception of Japan, I find that it is difficult to get a high level of construction technique. Only two countries have the technology to readily undertake this kind of timber construction: Switzerland and Germany. The building in Zurich went smoothly, as compared to those in France and Germany. Switzerland is not as strict as Germany, and the construction team was more precise versus working in France.

Everything is designed according to Swiss building conventions. I didn’t have to convince any authorities of anything. However, when I designed Metz we had to do a full-scale mock-up, and we tested it in Biel, Switzerland.

The Tamedia building combines traditional timber construction with cutting-edge technologies. Did you have doubts that the two could come together?
With Metz, we used a CNC machine to cut the laminated timber beams in 3-D, but for Tamedia the structure is only two-dimensional. We didn’t need the advanced 3‑D milling. The technology is nothing special, just a 2‑D CNC cutting machine. The budget was quite limited, so I had to do something very simple. Timber joinery is very economical. The facade is just a skin over the structural frame.

How does this timber construction lend itself to being sustainable and carbon neutral?
Carbon dioxide is an issue but not the main one. Even when I make a building out of paper, it is not about sustainability. It’s because it is beautiful.

Did you collaborate with a structural engineer?
It’s always essential for my design to start as a collaboration with an engineer. I have worked with Hermann Blumer of Création Holz on all of my timber structures. He knows what I like to do and how to do it. It is rare to find a timber engineer who shares the same ethos. Without his collaboration, I would not have been able to realize this project.

What is the future of wood construction?
It is difficult for me to look into the future. I don’t have a dream. Whenever I have a project, that’s when I start thinking about what material it should be. I’m not pushing timber on all projects. The project comes first, and then I design with a material that is the most appropriate.