1&1 – United Internet AG

Design staff restaurant within historic monument, Karlsruhe

United Internet AG wanted a new interior architecture and design concept for their company restaurants in Karlsruhe and Montabaur, which in future may also be applied at all other locations and to any floor plan.

The design concept should have a restaurant character with a modern atmosphere. The furniture should be of high quality, flexible and modular and be highly recognizable.

The first implementation of the design concept developed exclusively for United Internet took place in the listed, former thermal power station of Deutsche Bahn, which is located behind the main train station in Karlsruhe.

The thermal power station consists of a large boiler hall and an annex, the so-called coal chute, which, due to its height, was divided into ground and first floor. At the beginning of the 20th century, the trains moved into the coal chute to deliver the coal for the directly adjacent heating plant and “pour it out” in what is now the ground floor.

The architects Graf + Graf from Montabaur have integrated a gallery within the large boiler hall that appears to float. This impression is reinforced by a surrounding glass floor. As if on a tensioned ribbon, the stairs fold out downwards without seeming to touch the floor.

Space for a total of 360 guests has been created in the area of the gallery. A large terrace facing towards a quiet inner courtyard offers a further 44 seats outside.

The original character of the coal chute with natural stone walls, the high reinforced concrete beams and the raw concrete could be partially preserved in its original state. The historic steel construction of the roof in the boiler hall could also be adopted and integrated into the design concept.

The unusual architecture of the monument building, built in 1920, was a great support for an exceptional design result.


Architects: Graf + Graf, Montabaur
Photography: Nikolay Kazakov, Karlsruhe