Located on a campus stocked with office buildings from the 1980s with yellow-brick facades, administrators at EF Academy in Thornwood, New York, wanted to create a more dramatic and aesthetically pleasing appearance for its new dormitory. To achieve that goal, designers specified architectural precast concrete insulated sandwich wall panels along with precast concrete hollowcore plank that serves as ceiling/flooring modules.
The school, an international boarding school with additional campuses in Oxford and Torbay, England, decided to break with tradition and create a signature look rather than continue the existed, dated style. “The clients felt that they needed a more contemporary design sense, and they asked for a better aesthetic concept,” explains Brian Keating, principal at Scully Construction, the general contractor. “The dormitory looks completely different from the other buildings on campus.”
Key reasons why precast concrete was selected were its ability to provide a dramatic aesthetic as well as its ability to be prefabricated off-site and erected quickly once it was delivered. “We had a very aggressive schedule, and precast concrete’s fast erection helped us meet it,” says Keating. That speed was aided by the panels being cast 45 feet tall, so they could be set onto concrete foundations and lifted into place for the full height of the four-story building. Narrower metal panels with inset windows alternate with the precast panels, emphasizing the verticality of the design.
Coreslab Structures (CONN) Inc. fabricated the panels, which consisted of 22,600 square feet, while Oldcastle Precast Building Systems supplied the hollowcore plank. The panels feature a tight series of reveals that create the appearance of a board-form finish. The design created an issue for concealing joints on corners, notes Alan Simon, Principal at Simon Design Engineers.
“It became too much of a challenge to wrap the corners, so we created a joint just around the side from the main façade,” he says. “It was much better from a constructability standpoint to do it this way. Windows also were recessed inside the metal panels, requiring smaller returns on the panel edges.
The panels are 9-1/2 inches thick, including 3-inches of insulation. “The alternating precast concrete walls and metal panels created a challenge in terms of insulating the building,” Simon says. “Coreslab developed an innovative concept using two thicknesses of insulation to meet the R-value requirements while ensuring a smooth interior face.”
The panels load to the footings and are tied back to the steel frame for wind loading. The hollowcore planks were set into the framing inside the beams, ensuring the steel frame was flush-framed both on the interior and exterior. “We were very tight dimensionally, and the pieces came together very smoothly,” says Simon. “The steel frame is hidden inside the partition walls.”
The planks were left exposed with only a textured finish applied to the ceilings. “The client wanted to retain the industrial look of the exposed concrete for the ceiling panels,” Simon says. A leveling topping was poured for the floors, which were then carpeted.
The campus offered an open staging area that allowed the tall panels to be erected without constraint. “We were lucky to have a large site to maneuver on with our panels,” says Keating. “We could stage, pick, and erect the panels without worry.” Erecting the panels took only 1-1/2 weeks. “We had a good erection crew,” he notes. “Everything went very smoothly.”