Swiss Architect Cuts Building Emissions 66% Using Old Parts

A bright red wall in Switzerland hides an architectural revolution that could change how the world builds.

Peel back the metal façade at K.118 in Winterthur, and you'll find straw bales, recycled steel staircases, and massive beams from an old supermarket. Swiss architect Barbara Buser built this award-winning structure using 70 percent salvaged materials. The result? A stunning 66 percent reduction in carbon emissions compared to traditional construction.

At 72, Buser still bicycles through Basel visiting her projects, dressed in black with her gray hair in a ponytail. For decades, she's been saving abandoned factories and transforming them into thriving neighborhood hubs. Her secret isn't flashy new designs but rather asking a simple question: What can we save instead of what should we build?

The construction industry accounts for 12 percent of greenhouse gas emissions and over 35 percent of total waste in Europe. The European Commission estimates that smarter material use could slash those emissions by 80 percent. Buser has spent her career proving this isn't just theory.

Her firm Baubüro in Situ practices circular construction, reusing buildings and materials rather than demolishing them. The K.118 project featured 80 salvaged windows, reclaimed steel from a Zurich office building, and local clay coating the walls. Nothing was accidental, not even the imperfections.

"I've reached the point where I say we shouldn't demolish anything anymore," Buser says in her warm Swiss dialect. "Because of climate change, demolition simply no longer makes sense."

For years, Switzerland's professional architecture organization wouldn't accept her as a member because her work defied classification. Now they recognize she was simply ahead of her time. In 2021, K.118 won the prestigious Holcim Global Gold Award, one of the world's highest honors for sustainable construction. This year, Buser received the 2026 Jane Drew Prize for elevating women in architecture.

The Ripple Effect

Buser hasn't stopped at buildings. Together with collaborator Eric Honegger, she's launched over 20 companies devoted to circular construction, creating an entire ecosystem for sustainable building. She measures success not in Swiss francs but in CO₂ saved.

"If a project cannot meet strict carbon targets, it shouldn't be built," she says. Her philosophy challenges decades of architectural tradition that celebrated the tallest skyline and shiniest billion-dollar development.

As cities worldwide face housing shortages, rising construction costs, and climate crisis, Buser's work offers proof that solutions already exist. The materials needed for a sustainable future may already be standing around us, waiting to be reimagined.

Her projects show that the greenest building might be the one we choose not to tear down.