COMMERZBANK HEADQUARTERS

Frankfurt, Germany

1991-1997

Foster and Partners

The Commerzbank tower, the headquarters of one of Germany's major banks, radically reinvents the skyscraper. The conventional office tower has been cut open and turned inside out, so that the usual core of elevators, stairs and toilets is distributed to the corners of the triangular tower, leaving a hollow shaft around which spiral a series of sky gardens. Through these natural light and fresh air enter the hollow core and the offices that face in on it, thus bringing these to all parts of the building along with spectacular views, the close proximity of plants and the chance to socialize in the semi-outdoors. A double-layered facade that intercepts the rain and breaks the force of the wind allows even the outer facing offices to be naturally ventilated. For most of the year the building relies on natural light and ventilation alone during daylight hours. In the heat of summer, offices are cooled by chilled ceilings and in winter receive perimeter heating. Only in the middle of these seasons is the building also automatically sealed and air-conditioned, but monitoring shows this to be for less than the thirty percent of the year initially predicted. Energy efficiency is by no means the building¹s sole claim to greenness. It is responsive to its dual contexts of being both one of a cluster of towers and yet retains the street and cornice line of its setting. More importantly, the sky gardens, used for coffee, snacks and informal meetings, are part of a hierarchy of social foci, which include a communal space in the middle of each arm of offices and a lobby-level, covered plaza with restaurants used by both bank employees and public. Together these bring the social vibrancy and sense of community intrinsic to a fully green architecture. Shades of green: Low energy/high performance; total life cycle costing; embedded in place; access and urban context; health and happiness; community and connection

[photo credits: Ian Lambot; diagram:Foster and Partners]