What If We Never Built Another New Building?

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What If We Never Built Another New Building?

Instead of asking what should be built, Barbara Buser asks what can be saved.

Credit: Martin Zeller

By:<br>Michaela Haas

July 20, 2026

Swiss architect Barbara Buser has spent decades proving that the greenest building is often the one already standing.

When one unscrews a section of the bright red sheet metal façade from K.118, a former carpentry factory in Winterthur, Switzerland, the interior reveals something few people expect to find inside an award-winning contemporary building. Behind a gypsum fiberboard panel sit tightly compressed straw bales, packed as neatly as if they had come straight from a farmer’s field. Local clay coats the interior walls. The steel staircase once belonged to an office building in Zurich. Massive beams that now support the structure previously carried the roof of a supermarket distribution center in Basel. Eighty windows were salvaged from another building slated for demolition.

Nothing about K.118 is accidental, not even its imperfections.

Buser’s firm, Baubüro in Situ, built the three-story addition to the former factory using roughly 70 percent reclaimed materials.

“We could have used 100 percent,” she says, “but then it would have been more expensive than building new.”

Most importantly, the project cut embodied carbon emissions by nearly two-thirds compared with conventional construction, according to researchers at the Zurich University of Applied Sciences. In 2021, it received the prestigious Holcim Global Gold Award, one of the world’s highest honors for sustainable construction.

For Buser, the problem is that projects like K.118 remain the exception.

At 72, the Swiss architect still bicycles through her hometown, Basel, visiting her many projects on two wheels. Belying her unpretentious appearance — dressed in all black, no makeup, her gray hair loosely tied in a ponytail — she has become one of Europe’s most influential architects by refusing to build new construction. Instead, she has saved several of Switzerland’s signature abandoned factories and transformed them into lively neighborhood hubs, all by promoting circular construction: the practice of reusing buildings and their materials rather than demolishing them.

Barbara Buser. Credit: Gabriele Schaerer<br>For decades, the professional organization of Swiss architects didn’t even accept her as a member because her work is hard to classify, but now her colleagues acknowledge she was just way ahead of their time: She also recently won the 2026 Jane Drew Prize for elevating the profile of women in architecture.

Instead of asking what should be built, Buser asks what can be saved. “I’ve reached the point where I say we shouldn’t demolish anything anymore,” she says in her friendly, warm Swiss dialect. “Because of climate change, demolition simply no longer makes sense.”

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The construction sector is one of the world’s largest sources of greenhouse-gas emissions and waste, accounting for up to 12 percent of greenhouse gas emissions and over 35 percent of the total waste generated in Europe. The European Commission estimates that more efficient use of materials could cut those emissions by 80 percent.

For decades, architects have celebrated the next iconic building, the highest skyline, the shiniest billion-dollar development. But as cities around the world confront housing shortages, rising construction costs and the accelerating climate crisis, Buser’s work suggests that the materials needed to build a more sustainable future may already be here. The greenest building, she argues, may be the one we choose not to tear down.

Instead of aiming for maximum profit, Buser plans for “the social value” of a project. Credit: Martin Zeller<br>If she were in charge, “I would stop every project,” she says emphatically, “then review them all through the lens of sustainability. If a project cannot meet strict carbon targets, it shouldn’t be built.” Instead of measuring success in Swiss francs, she argues, “the currency should be CO₂.”

Buser is much more than an architect. Together with her longtime collaborator Eric Honegger, she has launched more than 20 companies devoted to circular construction, adaptive reuse and community-centered development. They range from her architecture practice to a consultancy for climate-conscious building, a nonprofit urban think tank, a company that refurbishes historic high-end steel kitchens, and organizations that match salvaged building components with new projects.

Cooperating with foundations and other partners, she often buys the projects she builds so she can fully implement her vision and keep rents low. Instead of aiming for maximum profit, she plans for “the social value:” “Humankind...