In the heart of Kollwitzkietz, mere steps from the protected water tower, an architectural audacity was realized: a residential building squeezed into a gap just 4.8 metres wide. At Belfortstraße 4 stands the "Link" – as architect Jo Klein calls it – nestled between two neighbouring buildings that embody different urban eras. The western structure sits directly on the street, its Gründerzeit proportions unmistakable. To the east, set back some 11 metres, sits a 1960s-era building. Between them lay the impossible space that became possible.

Berlin architect Jo Klein rose to the challenge brilliantly. With just 4.8 metres of width and 17 metres of depth to work with, he crafted an exceptionally thoughtful design. Two bay windows on the northern and eastern façades cleverly expand the living space toward the street and neighbouring courtyard, solving what could have been an insurmountable constraint. Every square centimetre counts here—the stairwell was pared down to the legal minimum of 1.5 by 1.5 metres, maximizing space for residents.The ground floor hosts a full-width commercial unit with glass frontage and garden access, plus the building's entrance and vertical circulation. Floors one through four each contain a well-proportioned two-bedroom apartment (roughly 70 m²) with courtyard-facing balconies oriented to capture northeast morning light and southwest afternoon sun. The crown jewel sits atop: a sprawling 150 m² maisonette across levels five and six, complete with a roof terrace—and room for a future pool.Structurally, Klein employed reinforced concrete shear walls, transitioning to a skeletal frame on the street-facing side. The building stays warm via district heating and radiant floor systems, keeping the design clean and efficient throughout.

www.jokleinarch.com

Photography Credits:

David von Becker
www.davidvonbecker.com

(Featured in CUBE Berlin 03|23)