Helical Bendheim Channel Glass Walls Grace Pennsylvania College

Stunning Curved Design by Steven Holl is a First in Exteriors

Eight helically-curved, double-glazed, 16-foot channel glass walls by Bendheim are key to the design of the new Franklin & Marshall College Winter Visual Arts Center in Lancaster, Pa. They clad the building’s 2^nd and Mezzanine levels and define its celebrated “box-kite” shape.

Steven Holl Architects designed the $29 million project – a three-story, 33,000 square foot building that opened in the fall of 2020. The unique building design curves in plan and section in response to several large, historic trees. “The trees are the largest thing of this campus. I made the actual geometry of the building concave in response to the diameter of the trees,’’ Holl said in a video on the company website.

Our ultra-clear low-iron channel glass with translucent white insulation creates a crystalline, brilliant white glass facade. Photo by Paul Warchol.

One of the main challenges for Bendheim was to engineer a unique, parallel, single-glazed, tip-to-tip framing configuration for the curved glass walls. The unusual façade layout, which has never been done before in North America, minimizes the visual appearance of the channel glass joints. Together with the use of translucent white insulation and ultra-clear low-iron channel glass, the new design produces a homogenous façade featuring a crystalline, brilliant white aesthetic.

Channel glass joints create a signature linear aesthetic, and tend to be fairly pronounced in traditional double-glazed applications. Typical to Steven Holl, the architect took a building material he frequently employs and made it brand new.

Bendheim detail drawing of the mezzanine level channel glass helix curve – elevation view

The customized facade configuration at the Pennsylvania college deemphasizes the joints and creates walls with deeper cavities, allowing the insertion of double-thickness insulation. This enhances the thermal performance of the wall and the diffusion of natural daylight. During the day, the helically-curved channel glass walls diffuse approximately 20 percent of visible light to the interior, eliminating glare – ideal for light-sensitive art studio environments. At night, they emit a subtle, visceral glow.

The building design allows for natural ventilation during mild times of the year, while geothermal heating and cooling, coupled with an insulated envelope, dramatically reduce energy costs. The project was designed to achieve LEED Gold certification.

National Enclosure Company installed the channel glass. Casali Group served as the project manager, while Harvey Marshall Berling Associates and Knipper Helbig Advanced Engineering served as façade consultants.