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Birdair installs tensile roof retrofit

Swatches | August 1, 2021 | By:

The Tensotherm™ fabric used in this retrofitted tensile roof offers diffused glare-free natural daylight, enhanced temperature control, remarkable acoustics and innovative sustainability. Photos: Birdair Inc.

Custom membrane provider Birdair Inc. has brought a modern look to a shopping mall in Lancaster, Pa., with the installation of a retrofitted Tensotherm translucent insulated tensioned membrane system. The three-layer Tensotherm roof replaced a single-layer tensile membrane roof Birdair installed at the Park City Center mall in 1988.

Tensotherm’s three layers include an outer polytetrafluoroethylene (PTFE)-coated fiberglass membrane, one layer of 8mm Nanogel® aerogel blanket and an interior PTFE acoustical liner. 

Birdair’s work on the 25,000-square-foot retrofit included design, engineering, fabrication and installation of the full replacement. With the help of Black Hawk helicopters, large fabric bundles were lifted from the adjacent parking lot and precisely placed on four different strategically built platforms for final installation of the new roof. This process was necessary because of the location of the center court. The Birdair team worked with JP2 Architects to complete the retrofit, and because the mall was open during the installation, crews worked during the night. 

When the mall was constructed in the early 1970s, its center court was enclosed with a solid roof structure. In 1988, the original roof was removed and replaced with a single-layer PVC tensile fabric membrane roof in a single conical configuration designed and built by Birdair. The roof is mounted from a central steel tri-cord mast about 100 feet in height, with supporting radial cables attached from the top of the mast down to the perimeter beam. Eight to 10 feet above the primary mall roof, steel beams framed the perimeter of the low tensile roof in an octagon 160 feet across. The top of the center mast features an aluminum framed hexagonal skylight.

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