For their “Blue Box” project in Prenzlauer Berg, Bruzkus Greenberg have radically redefined the concept of small space design, transforming a fragmented rooftop apartment in Berlin into a fluid, functional home centered entirely around a single, monolithic object. The challenge lay in liberating the original 75 sqm space from its labyrinth of walls and a poorly placed chimney, which stifled light and circulation. The solution was an act of reductive brilliance: remove everything, and insert a new core.
This core is the eponymous blue volume, a piece of dark, stained wood millwork that acts as the anchor and axis of the entire dwelling. As Peter Greenberg notes, the removal of the old fireplace allowed the dining area to become the new heart of the apartment. The millwork, stained to let the natural grain of the wood shine through, is meticulously crafted to contain the entryway, discreetly screen the stairs, and form a built-in banquette, seamlessly integrating several functions into one commanding piece of interior design.
The dramatic experience of the apartment is choreographed by this central unit. Upon entering, residents pass through the core itself—an intentionally dark and relatively low passage—before emerging into the main living space. This strategic contrast makes the primary area, defined by its tall ceiling and skylight, feel vastly brighter and more generous. “The dark and low entry makes the open space of the main room feel so much larger,” explains Peter Greenberg. He adds that “a sense of lightness comes not only because there are no dividing walls, but because there is a contrasting dark core”.
The project’s sophisticated use of color highlights the clear distinction between functional core and living space. The dark blue volume provides a horizontal grounding, while the continuous, sloping ceiling and the stairs are painted a bright, calming sky blue, literally drawing the eye upwards. This bold palette is accented by a major focal point in the main room: the bespoke, custom furniture piece named “Sophia 3000,” a voluminous butter-yellow sofa designed specifically by Bruzkus Greenberg to anchor the open plan living area.
Crucially, the apartment masters flexibility and spatial expansion through clever design tricks. A light blue curtain, stored invisibly within the cabinetry, can be drawn to separate the sleeping bedroom from the social spaces, creating a desirable “room within a room” that Partner Ester Bruzkus appreciates. Further amplifying the perception of space, a full-height unit with mirrored panels visually doubles the room and helps an existing structural column “hide in plain sight,” a subtle triumph of architecture over constraint.
Finally, the blue volume acts as a portal to the outdoors. The sky blue stairs lead directly up to the roof deck, which Bruzkus Greenberg treated with the same meticulous care as the interiors. This outdoor zone, complete with built-in seating and waterproof storage, is designed as “another important room of the apartment,” establishing a complete and comprehensive living experience that extends from the intimate 75 sqm interior right out to the sweeping Berlin views.