Sauerbruch Hutton - Germany
Zeppelinallee 8, Frankfurt
2005 - 2009

Sauerbruch Hutton Architects were commissioned with the planning of the KfW West-Arkade skyscraper as a consequence of a successful competition proposal from 2004. Situated in the city's West End district, adjacent to the central Palmgarten, this building complements a building complex from the 1970s, 80s and 90s. The new extension with an 15-storey tower contains conference facilities as well as office space for about 700 people. The KfW banking group, itself active as promoter of energy-efficient constructions, desired an energetically innovative and at the same time representative, visually impressive building for their expansion. Depending on the time of day and viewing angle one believes to stand in front of another building. The sophisticated high-tech facade adapts to the weather conditions, thereby changing its appearance. With the colored double layer facade, the architects created not only an unmistakable eyecatcher at the Zeppelinallee, but also realized a building with extraordinary low primary energy demand. To enable the inner facade to be used for natural ventilation with conventional windows, the outer facade has to balance the wind pressure. Operated by engines, the colourful flaps in the outer skin create a movable envelope, so that the contours behind are shown or hidden depending on the opening angle. The used colors are based on the environment. Blue refers to the facade colors of the adjacent KfW main building, red refers to the Main sandstone frequently used in prestigious Frankfurt buildings and the different shades of green are a reference to the adjacent Palm Garden. The skyscraper shines from behind the semi-transparent scurf fašade. It consists of a curved three storey base which follows the road cours, and the highrise volume twisted towards the Park. The shape of the tower takes into account the views of the neighbouring offices as well as the composition of the skyline. The tower appears as a slim slab towards the street, while it presents a discreet backdrop for the Palm Garden. At ground floor level, the fašade is set back to create a protective arcade towards the street. In 2011 the KfW-Westarkade building received the Best Tall Building in the World Award from the Technical University of Chicago.