Project DescriptionA new restaurant and event space serves as the social hub of the sprawling Trumpf manufacturing complex outside Stuttgart, Germany. The architects, Berlin- and New York–based Barkow Leibinger Architekten, have completed five projects on the campus. The honeycomb roof of their restaurant and event space takes its geometric cues from the surrounding buildings, including an office building that Barkow Leibinger completed in 2003. However, the firm’s design inspiration for the five-sided structure is essentially organic; the roof structure itself is based, biomimetically, on the idea of cells.
“We focused on the roof from the beginning,” principal Frank Barkow says. The architects worked with structural engineers to create a triangulated configuration of steel beams that would support the roof over 20-meter (approximately 65-foot) spans, allowing for a minimum of columns. Between the beams, in the place of conventional joists, are a series of pentagonal and quadrilateral cells made from fast-growth fir glulam boards stained with a white transparent coating. Glulam was a material, Barkow says, “that we were very interested in using because of its flexibility, its ease of use in CNC milling, and the idea of it being sustainable.”
Each cell comprises four or five boards, laid on end and secured with a series of screws to a triple-flanged steel element at the vertex of each angle. The only adhesives used during the construction process were ecologically friendly glues. The cells serve a variety of functions: Some accommodate skylights, some house direct downlights; others filter indirect artificial light through a 3-inch-thick aluminum grating; and still others incorporate a perforated wood screen that masks acoustical felt.
The cell structure provided “a kind of pixelated surface that we could code in different ways,” Barkow explains. Working with Matthias Schuler, a sustainable-energy engineer and an adjunct professor at Harvard’s Graduate School of Design, the design team determined the function of each cell in the ceiling. The strategy proved so efficient, Barkow notes, “we actually ended up closing up some skylight cells to save on costs.”