Regardless of the city, historic protection for a particular district typically restricts exterior alterations but allows much more freedom within buildings. This often results in a standard sleek-modern interior of the kind beloved by real-estate agents. Not so for the renovation of the Z22 House in Zurich. Architect Gus Wüstemann, a Zurich native who also runs a studio in Barcelona, has taken a thoroughly subversive approach to a 170-year-old, three-story house. What’s the most radical and at the same time most conservative thing he could do? His answer: strip the building’s interiors right back to their original structure and leave them as far as possible like that.

On the exterior, this house in the Riesbach neighborhood, toward the southern edge of the city’s center, looks like many of the plainer mid-19th-century buildings in what is now an affluent district. Set a little way up the hillside overlooking the clear waters of Lake Zurich, nothing seems remarkable from the sidewalk: a pedimented neoclassical frontage, a white stucco facade, wood-framed windows, and a pitched roof. But when Wüstemann produces his bunch of keys and lets you in, you step into something that is a celebration of raw structure.