Sauerbruch Hutton

The GSW headquarters in Berlin is an assemblage of five building volumes that extend an office tower from the 1950s. A prototype at the time of completion, this project embodies the paradigm of ecological architecture of the 21st century in an exemplary manner.

The building's individual components reflect the characteristic traces of its urban environment's episodic development and make them visible. At street level a gently curved volume redefines the public space and forms a plinth – with its position and height referring to the earlier baroque city. Seen from the east, the slender high-rise slab acts as a backdrop for the existing tower, while emerging with an assertive presence to the west. As a compositional counterpoint, the so called pillbox balances on the eastern end of the plinth, with its height referring to the buildings of the Gründerzeit. This strategy of retrospective integration embeds the previously solitary tower into the urban fabric while acknowledging the historically evolved conglomeration of Berlin as a structural principle.

The slender layout of the new high-rise optimises the use of daylight and ensures cross-ventilation for all offices. Room-high movable screens of perforated metal define the entire west façade and provide effective solar protection. These are fitted in a cavity of the double-façade that functions as a convection shaft allowing natural ventilation on the high-rise floors. An aero-dynamic wind roof enhances this effect. With various shades of pink, orange and red the solar shades make the building recognisable from afar. The individually operable elements respond to daily and seasonal changes, generating new colour compositions again and again. Thus, the west façade illustrates the ecological aspects of the building while, in addition, turning into a perpetually changing kinetic image.