Located on a promontory on Staten Island overlooking New York Harbor, 102-year-old Curtis High School stands strong after a $25 million façade restoration effort.
The 30-month project, headed by the New York City School Construction Authority and New York-based architect/engineer STV Inc., involved restoring and replacing more than 12,000 pieces of terra cotta, brick, and limestone that make up the school's elaborate Collegiate Gothic façade.
Designed by architect and long-time superintendent of New York City School Buildings C.B.J. Snyder, the school's ornate gothic elements had taken a beating from constant exposure to high winds and salt water, poor maintenance, and the inadequate construction methods of the time, says Leonard Sherman, project architect with STV.
"At some point, all the terra cotta was treated," says Sherman. "But instead of re-pointing the masonry, they just caulked it, which sealed in any water that got in and accelerated deterioration."
Where possible, the Building Team introduced expansion joints and cavity walls to facilitate drainage and thermal expansion, including parapets and towers. Where minor terra-cotta or brick replacement or restoration was needed, each piece was "surgically removed," says Sherman.
Construction documents on the original 1902 structure were nonexistent, and documentation on five subsequent additions constructed between 1921 and 1964 was often inaccurate. CDs on the classroom building (1921), for instance, indicate a steel structure, but upon inspection, STV discovered a concrete frame. "They changed the structure and never updated the drawings," says Sherman.
In attempting to restore the structure's three-story projecting bay window, they discovered that cantilevered outrigger beams that were supposed to support the extension of the slabs beyond the face of the building were never installed. As a result, the façade became load-bearing, placing a huge weight on the bay's under-designed lightweight steel support structure, which eventually failed.
The team gutted the projecting bay down to the structural concrete floor slabs and inserted a concealed galvanized steel structural tube system that transfers exterior wall loads at each floor back to the primary concrete beams.
When the upper portion of a 120-foot-tall tower in the 1902 structure was found to be structurally unstable, the team disassembled the original load-bearing terra-cotta walls down to roof level and replaced them with reinforced structural brick parapet walls. The new terra-cotta veneer is anchored off these walls.
Stone Creek (Ohio) Brick Co. replicated the school's beige brick. The job called for custom molds to match the unique sizes, which varied from 8 to 8¼ inches in length. Color was difficult to replicate, because pollutants from old coal-burning plants across the bay had discolored the brick.
Reconstruction Awards judge Greg Mulac of Turner Construction, New York, was particularly impressed with documentation showing how 25,000 pieces of stone were identified, labeled, and evaluated over a six-month period by STV and New York-based Jablonski Berkowitz Conservation. Nearly half were replicated and replaced using more than 1,000 different molds.