[Image by Willem Vogel]
Earlier this fall, BUILD sat down with Walter Unterrainer at Chalmers University in Gothenburg, Sweden. His career is defined by experimentation—bridging hands-on practice, academia, and a deep commitment to transforming the existing built environment. Unterrainer challenges architects to look beyond the allure of the new and engage more critically with resourcefulness, reuse, and the cultural value of what’s already here.
Tell me about your background and how you arrived where you are today.
I’ve been practicing architecture for about 45 years. Early on I founded my own office as a “practice of controlled experiment,” always looking for alternatives to mainstream building because I found much of it too costly, dull, and environmentally careless. I worked across seven European countries on projects ranging from small experimental buildings to large urban redevelopment, which exposed me to very different building cultures and regulations.
My experimentation focused on design process, materials, and construction. I used participatory design decades before it was a trend, sometimes involving self-building. I explored low-energy construction and prefabrication for more affordable housing. One project using cardboard insulation behind a glass façade even received the Austrian State Prize for Architecture. But I never approached this as an engineer—I’ve always seen myself simply as an architect aiming to create excellent space, choosing materials according to context rather than ideology.
In parallel, I’ve taught widely. I began teaching part-time in the mid-1990s in Switzerland, Liechtenstein, and Austria, then helped launch a European–Chinese master’s program in sustainable architecture with Tsinghua University. That work led to a professorship at Umeå in northern Sweden, then seven years in Aarhus, and now Gothenburg, where I teach at about 70% and keep a very small practice, taking on only the projects that genuinely teach me something new.
[Lot Eingangsbereich image courtesy of Walter Unterrainer]
What originally led you to add teaching to an already busy practice?
I began with part-time teaching, which was invaluable for someone doing experimental work. Universities offered access to labs and academic expertise, and in return I brought practical experience into the classroom. It created a productive exchange between practice and academia.
In 2010, while I was a professor in Umeå, I had a major heart attack. Surviving it made me reconsider my pace, so I sold my office to my employees and shifted fully into academia—though I kept a very small practice on the side.
That practice became quite meaningful. Clients whose homes I designed 40 years ago began returning because their lives had changed and they wanted to adapt their houses. Revisiting those early projects is both challenging and rewarding; I design as I do today, but in conversation with my own earlier work. It’s a dialogue between the new and the existing—and with my younger self—and those are the projects I still take on personally.
What are you most focused on in your teaching and research now?
I focus almost entirely on transformation of existing buildings. I don’t teach the design of new freestanding buildings on blank sites. Of course, transformation can include extensions, infill, vertical additions, and so on, but the basic premise is that we work with what already exists.
[Image by Jacquelin Maude]
What does that mean in the context of an academic design studio?
We retrofit abandoned schools or industrial buildings, adapt churches that are no longer in use, transform railway stations. The spectrum of master’s theses I supervise is very wide. One student, for instance, is working on transforming what was known as the “human slaughterhouse” in Damascus during the Assad regime, where people were tortured and killed. The project aims to turn it into a place of healing, memorial, and remembrance. Another student is building a catalogue of truly sustainable timber constructions—from the forest to end-of-life—always with architectural quality.
So the range in my academic studios is broad and the goal is never just to optimize technical performance; it’s to create meaningful space.
Explain why society needs to shift away from demolition and expansion toward transformation.
For decades architects were trained as if there would always be an empty plot waiting for a new object. The project brief was typically something along the lines of here is an empty lot, maybe it has some context, now design a new building. Working inside existing structures was not taken seriously as a primary task.
In Sweden I find it particularly strange. Here in Gothenburg, for example, I have documented the demolition of an entire urban block in Gårda over just half a year. Sahlgrenska Hospital is being demolished right now in a way that I consider effectively illegal under European guidelines. They are doing it like they would 50 years ago with heavy machinery crushing everything together and almost no meaningful separation of materials for reuse.
There is a lot of talk about reuse and upcycling in Sweden. People tell themselves they are world leaders, but on large projects I see very little actual practice. While reuse and upcycling are happening at the small scale, the big companies are not leading by example.
How does this shift toward transformation change the role of the architect?
The answer varies by country. In places like Austria, Germany, Switzerland, and France, “architect” is a protected title tied to clear responsibilities in construction, detailing, and site supervision. In much of the Nordic region, by contrast, architects often produce early designs that are then handed to contractors, who build in whatever way is most profitable, with limited regard for architectural quality.
Because the degree of influence differs so widely, the role changes differently in each context. But everywhere, transformation demands deeper engagement with construction and existing fabric—not just producing forms, but understanding how buildings are actually made and adapted.
In your studios, how do you connect these real-world issues with the education students receive?
I do it in several ways. First, I show best-practice examples from around the world. Many students only know their immediate surroundings, which limits their sense of what’s possible.
Second, I support their visions rather than dismissing ideas as “not feasible in Sweden.” When a project invites skepticism, I point to built projects that prove otherwise. What’s possible is shaped by people and politics, and those conditions can change.
Third, I introduce the idea of unsolicited architecture. Some European practices—and I myself (myself in the past, not any more)—don’t wait for clients. They identify a problem, propose a solution, and secure the legal and economic framework so the concept can’t simply be taken over by others. In that model, you effectively design the project, the client, and the budget, shifting the power dynamic so the architect chooses the right investor—not the other way around.
[Image by Willem Vogel]
The culture around architecture, popular media and often education—still tends to celebrate the brand-new object. How do you help students unlearn that?
I think the peak of that culture is actually past, at least in our context. The idea that the solitary new object is architecture’s highest goal is no longer dominant. The performative side of architecture—what buildings actually do for people and cities—has taken precedence. Architecture is increasingly understood as the frame for life, not an object to admire, and isolated objects can be meaningless or even harmful to the environment and urban fabric. For me, the essential question is always: What is this building doing to the city and to the people who use it? The “starchitecture” culture that was so strong 10–20 years ago has largely faded; a few students are still intrigued by it, but they’re now the exception rather than the rule.
What tools do you give students to help them measure the value of reuse and low-carbon design?
We use advanced simulation tools to model whole buildings and compare operational and embodied energy. Students can see how heating, lighting, and cooling demands relate to the carbon locked into materials—and how improving insulation or adding structure can shift that balance.
The software isn’t the hard part; students learn it quickly. What’s challenging is interpreting the results and knowing where to adjust— geometry, window orientation, glazing, room height, acoustics, and so on. That’s where experience and architectural judgment matter, and that’s what I focus on teaching.
[Image by Jacquelin Maude]
Describe a studio project that connects your academic work with the realities of construction.
I teach an intensive workshop in Master education called Reverse Tectonics, which students respond to very strongly. They’re given a 3D model of an unfinished three-storey concrete frame—like the many abandoned structures left after bankruptcies across Europe—along with an inventory of about 35 materials, some conventional and some unexpected: timber boards, roof tiles, pallets, rails, boats, shopping carts, seaweed, old mattresses, and so on. Their task is to complete the building using only what’s provided.
Instead of the usual process—brief, site, budget, and a made-to-order materials list—this is more like cooking a good meal with whatever’s in the fridge. The results are wild and often beautiful in their imperfection. Students choose a plausible program but don’t focus on detailed layouts; the real goal is hands-on thinking about tectonics, reuse, and transformation.
[Image by Willem Vogel]
Talk about your philosophy of “radical prefabrication.”
I can explain it with a story. In 1993 I built an extension to an old house. From the start of the foundation work to moving in, it took nine weeks—including everything. Much of this success was due to our curiosity and ambition: how fast and how well can we do this? The other factor was the age of the clients: she was 73, he was 83. Part of their old house had been declared uninhabitable, so we had to demolish it. They had to live in extremely limited conditions during the construction period, so you want that period to be as short as possible. Both had a great sense of humor. We joked that for an 83-year-old, a delay on site can literally be a matter of life and death. He laughed and agreed. From that project I developed a notion of radical prefabrication.
What could policy and government do differently to support the kind of transformation you’re describing?
My knowledge of Swedish politics is not deep enough to comment in detail, but I can give an example from Germany. There, universities, significant offices, and the architects’ associations together have pressured the government to regulate demolition more strictly.
They’ve proposed a moratorium on demolition—a year during which no demolitions would be allowed. After that, they argue that demolition should require the same level of documentation as new construction. Today, if you build a new house, you must document all kinds of things. It should be the same for demolition: What exactly are you destroying? Why? What is the material value? What are the social and environmental consequences?
Much demolition is simply driven by tax incentives—it’s cheaper and more profitable to tear down and build new, then write off the investment. That is what I call “brainless demolition.” It’s socially problematic, economically short-sighted, and environmentally destructive.
Are there cities or regions that exemplify a more caring, transformative approach to existing buildings?
There are areas in Central Europe—southern Germany, parts of Switzerland, parts of France and Austria—where environmentally conscious building culture is relatively strong. But a very interesting case is Italy.
With all its pros and cons, Italy has a clear attitude: many of their cities are among the most beautiful in the world, with buildings 400–600 years old. They don’t need to discuss the sustainability of those buildings; they simply accept them as part of their life. The climate helps, of course, but more important is that they love their built heritage. You don’t destroy what you love.
Demolition levels in Italy are relatively low, and they don’t try to make every little village fully accessible by car in every backstreet. That restraint is also part of building culture.
As someone who has practiced for decades, how did you convince clients to invest in low-energy, renewable solutions that are often invisible, instead of spending only on visible luxuries?
Those conversations didn’t really exist, because you get the clients you deserve. If you don’t compromise your principles and don’t fill your portfolio with projects that betray them, you tend to attract clients who come to you precisely because they want something they can’t get elsewhere. They arrive already interested in low-energy, environmentally responsible architecture.
I also received many commissions through competitions. In those projects I often integrated environmental performance not as a technical add-on but as an architectural quality. That combination was appreciated by juries and led to built work.
You’ve described “building culture” as the foundation of sustainability. What do you mean by building culture?
Building culture has many dimensions. One is how people relate to the city, to nature, and to their neighbors. Another is how we understand space personally: what kinds of rooms make us feel comfortable or happy, and how size, proportion, light, acoustics, materials, colors, smells, temperature, and fresh air shape that experience. I find it fascinating that many people who care deeply about quality in some areas—buying an expensive electric Porsche, for example, often choose the cheapest possible options when building a house: doors, floors, furniture. Not everyone does this, of course, but it’s common enough to form a pattern. At the same time, I know people living in small, modest houses with remarkable care and coherence—where people and place form a unity down to the lamp in the corner. That, to me, is building culture.
It’s also striking that we don’t teach architecture basics in schools. Given how fundamental space is to our health, economy, and well-being, it’s remarkable that children grow up without learning how to understand or shape it.
What three books do you think every architect should have on their shelf?
Architecture Without Architects by Bernard Rudofsky. It opens your eyes to vernacular and anonymous architecture and shows how much we can learn from it.
Und hinter der Fassade by Wolfgang Kabisch, which marked the shift from object-oriented thinking toward a performative understanding of architecture—what buildings actually do rather than how they look.
And for architects in academia, I often recommend Stop Making Sense by Angelus Eisinger. It’s about knowledge production and takes a critical view of a certain type of academic “research” where people just endlessly quote each other without producing new insight. I’m really fed up with that.
Walter Unterrainer is a professor of Architecture and Resources at Chalmers University of Technology in Gothenburg, where he focuses on the intersection of architecture, sustainability, and economics. Originally from Austria, he led his own architectural practice for many years before transitioning into academia. His work bridges sustainable building design, ecological construction methods, and financial viability in architecture. At Chalmers, he is known for integrating economic frameworks into architectural education and for challenging students to think critically about resources, materials, and long-term environmental impacts.