Necessity is the mother of invention, and at the new headquarters of the Fondation Jérôme Seydoux-Pathé, in Paris, a complex site with severe constraints gave rise to a shiny, bulbous, but elegant building that some critics have called one of Renzo Piano Building Workshop’s (RPBW’s) best works. The 23,000-square-foot, five-story structure houses offices, archives, exhibition space, and a 70-seat screening room for the foundation, which is dedicated to celebrating the legacy of the pioneering French film company.
Located on the historic Avenue des Gobelins, the 9,000-square-foot site includes a landmarked façade adorned with bas-reliefs by a young Auguste Rodin, which had to be incorporated into the new building. The site widens and bends as it extends away from the street, and is hemmed in by a collection of mid-rise apartment buildings. Inserting a traditional, box-shaped building onto the site, says Thorsten Sahlmann, RPBW’s architect in charge, would have obstructed views and cast hard shadows onto neighboring structures.
The design team began imagining how a creature might adapt itself to the site. Completed in 2014, the result features a long, organically shaped, glass vault clad in perforated aluminum panels that drew immediate comparisons to an armadillo. The bulk of the structure’s volume is concentrated near the site’s center, where it rises five stories at its crest and then dips dramatically at its ends, preserving neighbors’ views and access to daylight, and rendering itself nearly invisible from the street.
Perhaps the building’s most transcendent space is the fifth-floor research center, housed in the voluminous vault with 32 exposed parabolic wood arches, with spans ranging from 10 feet to upward of 50 feet. In cross-section, the longest arches assume a banana-like shape in midspan due to a 4-inch increase in depth as compared to the base, a structural requirement.
RPBW chose laminated larch wood for the arches, for both its look and flexibility. Glulam beams can be cut to any size, Sahlmann says—something the firm tested at its Peek & Cloppenburg store in Cologne, Germany, which features a similar roof structure. The difficulty in the Pathé project, he says, “was the shape and the aesthetic because obviously we wanted a perfect wood surface.” To ensure the wood would meet expectations, Sahlmann flew to the timber contractor Rubner Holzbau’s fabrication facility in Bressanone, Italy, and approved each arch before it was transported to the site.
Given the site constraints, the largest arches had to be delivered in two pieces and then joined by embedded steel plates and bolts. The arches tie into a steel beam that runs the building perimeter—because “the edge of the concrete shell [encasing the second through fourth floors] was not stiff enough to take the load of the arches,” Sahlmann says—and then braced by a double-curved steel superstructure, which ties into the concrete shell.
The vault shell, which comprises double-curved glass, creates a 100-foot-long domed skylight. Seven thousand curved aluminum panels, or lamellae, form an outer skin over the glazing, as well as the rest of the concrete structure, and functions as a brise soleil, diffusing sunlight and shielding Pathé employees from curious neighbors. “We wanted to separate the layers by not directly putting the glass on the wood, so you can recognize each layer of the roof structure,” Sahlmann says.
RPBW’s 3D models of the building envelope, created using CATIA and Rhino, were so complex that it took months for the project team to find a façade contractor willing to build it. “We negotiated for nearly for nine months with several contractors,” Sahlmann says. “[During] this period, we convinced the contractor that our 3D model could be used for the production process.” Contractors typically create their own models due to liability issues, but for the Pathé Foundation, re-creating the model would have been time- and cost-prohibitive. RPBW also simplified the aluminum skin by faceting it into smaller panels to eliminate the need for double-curved panels. Eventually, façade specialist and contractor Frener & Reifer, also based in Bressanone, signed on. The aluminum panels required two months of fabrication, while the wooden arches and double-curved glass required three months each.
Despite its similarity to an armadillo’s plated carapace, Sahlmann maintains that any resemblance is coincidental—call it accidental biomimicry. “Everybody told us, ‘That looks an armadillo,’ ” Sahlmann says. “We finally looked for some pictures, put it next to our drawings, and said, ‘Yeah, it’s true. It really looks like an armadillo.’ ” Even the structure—with its rib-like glulam arches, double-curved glass shell, and overlapping aluminum scales—approximates the animal’s anatomy, whose armor consists of a bony bottom layer topped with keratin scales, or scutes.
“When we designed the grid of the façade, it took us a little time to [reach] the current design,” Sahlmann says. “Maybe we should’ve looked at [armadillos] earlier.” However, architects can only draw so many lessons from the animal kingdom, as the headquarter’s and mammal’s structural systems serve two different purposes, he notes. “Like Renzo says, ‘In the end, the building is a building, and the armadillo is an armadillo.’ ”
