competition for a multifunctional urban centre in a prefabricated slab housing estate for professor peter baumbach, with urs löffelhardt and frank lang

transformation of the ‘prefabricated slab building typology’ into spaces and typologies for urban density

In a mono-functionally organised residential landscape consisting of 11-storey buildings, a larger empty site offers space for a centre that aims to create improved identification and urbanity. In the search for a significant form for this centre space, we did not choose the vertical dominance set in the empty space, but the “overturned slab”, which as a large form shifted into the horizontal, offers correspondence to the adjacent vertically oriented bodies in its memorable expressiveness.

In the transformation of the slab into a lying body, an interior landscape is formed that ties in with the meandering spatial forms of the green corridor in a differentiated and reduced form, thus ensuring spatial continuity in the whole while remaining closed off from the outside. Through its change of position, the large form has undergone a metamorphosis that makes it porous and permeable: It receives openings and breakthroughs of different order, which correspond with its multifunctional structure of use. Underneath the tilted and broken slab are glass slivers that fragmentarily mark the transition from the surroundings (landscape or terrain modulation) to the architecture (slab), the transition from outside to inside.

While the space bounces off the standing slab or passes it by without any support, so that no differentiated intensity on a human scale emerges, the horizontally floating slab draws the space underneath it. Flowing spaces emerge beneath it that interconnect with the surroundings in a variety of ways. The contrast between the vastness in the residential area and the dense spatial landscape in the centre area with variously shaded transitions from the private to the semi-public to the public is intended to create an attraction that promotes memorability, identification and encounters.

The result is an urban centre that derives its special character from a dense structure and building types with mixed functions. Since density and a mix of functions are essential characteristics of urban living, the desire for urbanity and the specification of a 35% degree of sealing are mutually exclusive. In view of the low density or sealing throughout the residential area, adherence to this specification did not seem desirable to us.

Building areas 1-3 are drawn together into a whole via the outer edges of the building. The two-storey slab sits on top of two transparent storeys. This creates the impression of a closed 3-4-storey structure from whose interior another structure, the multi-storey car park, emerges. The roof is seen as a fifth elevation because it is visible from all sides. Whereas on Siriusstraße the building is closed and thus creates a city edge supporting the space, the 2-storey slab on Schönefelder Chaussee extrudes significantly into space, convex components mark the entrance to the pedestrian zone, concave ones accommodate the pedestrian traffic from the bus stop. The basement on the pedestrian zone is transparent and draws the outside space into the interior. At the end of the building, a slab cut-out provides a harmonious connection to the town square and the adjoining green corridor.

With the aim of equalising the traffic routes, we have layered the paths. Pedestrians are guided across the delivery of the supermarket and the department stores’ and the entrance to the multi-storey car park without any crossings. The backfill on the side of the supermarket avoids residual space and can accommodate excavated material. The first part of the building offers space for retail, hotel and multi-storey car park, which is enclosed in the lower area but remains perceptible as a body. A green zone is inserted between the first building section and the existing consumer market, which also serves as a cross connection for pedestrians. In the third part of the building, a two-storey, transparent building structure under the slab offers space for services and practices. It is interspersed with passages that connect the pedestrian zone and Siriusstrasse. They lead across a small inner square and are lit via openings in the slab. The slab itself contains mainly flats. There are visual relationships between the two areas – spaces that range in character from public to private.

The overall concept is based on a mixture of functions. The optimal integration of the residential building is linked to the function of the basement floors – in our opinion, this makes its integration mandatory. A satisfactory urban solution along Siriusstrasse is also not conceivable without the mass of the housing. In the first section, the park, retail and hotel functions are arranged, in the second section, a link is created behind the shopping centre with a shopping arcade and offices above, and in the third section, services, practices, flats and the community centre are accommodated in mixed building types. The structures are open, so that different functions can be stored and developed, as well as exchanged. All parts of the building are organised to be accessible for the handicapped. On Siriusstraße there are mainly smaller flats suitable for the elderly on two upper floors. Larger flats as maisonettes are planned to the north of the small interior square. In the basement, mainly services and practices are accommodated. However, dense areas can also be used as retail facilities. The problems of lack of privacy that normally arise in high-density apartment buildings are solved by placing the flats on the upper floors. The floor plan geometry ensures that privacy is maintained.