Located in Prenzlauer Berg, Berlin, PR33 is a rooftop residential extension by HAA&D atop a historic 1906 building. Spanning 874 square metres, the project introduces new housing within an established inner-city block while working with the form, scale, and architectural identity of the existing structure. Rather than using contrast as its primary strategy, the addition is conceived as a continuation of the building below: a contemporary intervention that draws from inherited proportions, massing, and urban presence while meeting current standards of comfort and energy performance.

As a form of rooftop densification, the project creates new residential capacity without consuming new land. It builds within the existing city, making use of established infrastructure, a connected neighbourhood, and an already occupied urban plot. In this sense, PR33 exemplifies a low-impact growth model in which housing expansion is achieved through adaptation rather than outward sprawl.

Building within an existing urban framework
Set at a prominent crossroads, the original building is defined by traditional proportions and a cross-shaped configuration. The rooftop addition takes these characteristics as its starting point, translating them into a contemporary architectural language that respects the streetscape while remaining legible as a new layer. This approach allows the project to read as an evolution of the building rather than an object imposed on top of it.

The intervention required a holistic process that combined structural adaptation, compliance with Berlin’s regulatory framework, and management of the building’s visual relationship to its urban surroundings. The design therefore treats sustainability not only as an issue of energy or materials, but also as one of continuity: preserving the value of existing city fabric while accommodating new forms of residential use. By extending rather than replacing, the project retains the embodied value of the structure below and contributes to a more resource-conscious model of urban renewal.

Continuity through abstraction

The project’s material and geometric strategy mediates between old and new. Rather than copying historic details, the design abstracts elements of the 1906 building and reinterprets them through contemporary construction. This produces a layered architectural expression in which continuity is achieved through proportion, rhythm, and massing rather than imitation.