When Jeff Marshall, senior project manager at Irvine, Calif.-based C.W. Driver, talks about the Cal Poly Pomona Student Services Building, he is quick to point out that it was the largest challenge the project team ever faced in designing and building a project. As the project’s construction manager providing both preconstruction and construction services, he says this was mostly because of its unique, curved metal roof structure; a roof that he says had never been completed before anywhere in the world.
Unique, undulating, aluminum standing seam roof pushes building material boundaries
Photo: Timmerman Photography Inc./Bill Timmerman
However, in spite of its labor intensity, the roof impressed 2020 Metal Architecture Design Award judges enough to award it the top spot in the metal roofing category.
“The support structure for the roof consists of 1,200 tons of structural roof steel of varying sized members, with almost no members meeting/intersecting at right angles,” Marshall says. “This sub-structure was designed in a virtual environment in advance of being fabricated or erected, so that the roof panels themselves could be pre-made. The rolling machine that produced the panels booked out months in advance and had to be shipped from Dubai, just to roll the roof panels for the project. Further complicating things was that the tolerance for the placement of each of the 20,000 clips that supported the roof panels, was less than one degree in each plane, at each clip location—the clips sitting on either concrete or structural steel. This tolerance far exceeds the tolerances associated with typical building construction.”
CONTINUOUS CANOPY ROOF
The Student Services Building is designed as the new visual gateway to the Cal Poly Pomona campus in Southern California. A hub for prospective and returning students, alumni and visitors, it houses vital student services and administrative functions, and stands as a welcoming place of arrival. “Sustainably designed and engineered, the design draws inspiration from the surrounding San Gabriel mountains and foothills that are articulated in its curving shape and the form of its standing seam aluminum roof,” says Alex Korter, AIA, RIBA, LEED AP BD+C, associate principal, CO Architects, Los Angeles. “This place- and performance-driven design approach unites the building with the landscape and demonstrates the university’s commitment to sustainable practices.” The structural engineer was John A. Martin & Associates, Los Angeles.
Organized into two wings, the building is sited on a natural campus pedestrian path and bisected by a central breezeway but covered by its unifying metal roof. The roof consists of 95,000 square feet of 18-gauge standing seam aluminum panels (both perforated and solid) in natural aluminum color with an AluPlus patina finish in eight different panel types from Kalzip, Valparaiso, Ind. The breezeway is enveloped by the continuous canopy roof, which is perforated to provide daylight while shielding this public area from direct overhead sunlight. Korter says the perforations—combined with the deliberate shaping of the breezeway—allow for air to move through the public space below, creating a pleasantly cool exterior space that is utilized by the entire campus.
The 2-acre curved roof is the primary energy performance driver and passive building system, balancing shade, heat gain and daylighting levels. Large, 28- to 30-foot-wide overhangs protect the building’s glazed exterior walls from the sun. The edges of the roof are perforated to filter dappled sunlight and increase daylight autonomy while minimizing glare. The metal panel installer was CMF Inc., Orange, Calif. “CMF performed 2,400 lineal feet of welds on 2,400 panels,” says CMF’s president/CEO Dave Duclett. “A total of 103,000 square feet of roofing surface with 12 clerestories was supported above the substrate. After undergoing the biggest week-long storm in several years, there were no leaks.”
COMPLEX GEOMETRY
The roof’s geometry extremely complex and designers knew it was going to be a challenge to communicate and coordinate using traditional tools like drawings. “It was modelled, analyzed and coordinated using various digital technology tools,” Korter says. “The approved permit drawing set only included one drawing describing the roof topography; all other information was transmitted to the contractor solely through a digital model. This roof building information model was then transferred to the roof fabricator for optimization and rationalization of the roof panels. Panel geometries for the panels were extracted from the model and the data was directly fed into the panel-generating machines on-site, turning aluminum coil material into interlocking, standing seam panels ready to be installed.”
The judges appreciated the roof’s complexity. David Dowell, AIA, partner, el dorado Inc., Kansas City, Mo., says he loves the project and what he likes particularly about it is, “It is as much about what’s underneath it as what’s on top; which is an accomplishment—nothing but multiple thumbs ups for it.” In his evaluation, Rick Harlan Schneider, AIA, APA, LEED, principal at ISTUDIO Architects, Washington D.C., says he was fascinated with the form and shape of the roof. “The combination of the perforated metal along with the solid metal for the roof made an organic form,” he adds. Stephen Van Dyck, AIA, LEED AP, partner at LMN Architects, Seattle, felt the metal roof was its signature move that tied everything together. “The roof gives it scale and presence in a unique form and using metal is key element of the whole project,” he says.