Rheinkalk GmbH, Wülfrath

The new building was constructed following the consolidation of the Rheinische Kalksteinwerke GmbH and the Rheinisch-Westfälische Kalkwerke AG into Rheinkalk GmbH under the Belgian Lhoist Group in 1999. The headquarters were to provide some 120 employees an opportunity to launch a new start together under a single roof. In terms of the design, substantial emphasis was placed on creating space for improved formal and informal communication within the company as well as on low-energy technologies.

The elongated building with a floor plan in the shape of a large “H” is situated somewhat to the west of downtown Wülfrath on the site of a former stone quarry, a property with a sharp incline. Due to its soft, rounded corners, the outline of the building is similar to that of a butterfly. And due to its perfect symmetry, the building makes an almost stately impression, certainly as one approaches the entrance with its large, projecting roof made of steel and glass. The curved external cladding extending across the building and the continuous bands of the sunblind grilles — both made of matte aluminum — lend the architecture an unusually homogeneous and dynamic quality.

Inside the light-filled foyer the visitor’s gaze is immediately drawn into the depth of the space, toward the stairs leading to the floor above and the glass wall bearing photographs by the Swiss artist Beat Streuli. His panels with portraits of people from throughout the world are not only reflected on the floor but also on the curvature of the balustrade above the vestibule. Behind the glass wall are a café and a
restaurant, both with access to the terrace looking out onto the garden courtyard.

The main elements of the building, however, are the two practically identical office wings to the left and right of the foyer. Individual
and group offices are laid out one after the other on both the lower and upper floors. The size of these offices can be easily altered due to the grid dimensions of 1.35 m. The office walls facing the hallway are largely made of clear glass. Blinds make it possible to close off the offices from view. Frames and doors are made of beech wood. The hallways widen midway down their length. In each hallway shared technical equipment, an espresso machine, and a table with chairs for short meetings have been placed, forming a kind of island.

Whereas here small spotlights on the ceiling provide artificial lighting, one or more standing lamps are used as lighting sources for the workspaces in the offices. In the office wings of the building the artificial light has a white, diffused quality, whereas in the foyer the light has a yellow, spot-lit effect.

The natural flow of air is used in winter to warm and in summer to cool the building. On hot days the air is drawn through the central areas of the office wings and out of the building by a ventilator. The partial vacuum in the offices subsequently draws in fresh air from the outside through air circulation vents beneath the windows in alternating axes of the building. This makes it possible to maintain a stable temperature in the building—without incurring high costs.

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