Birdair, Inc. Completes World’s First TensothermTM with Nanogel® Project

Birdair, Inc., the leading specialty contractor of lightweight long-span roofing systems and tensile structures throughout the world, has completed a retrofit roofing construction project on the Dedmon Athletic Center at Radford University, Radford, VA.

When considering new roofing options for the 52,000 square-foot Dedmon Center – nicknamed “The Bubble” by students and faculty – energy efficiency, moisture resistance and sound dampening topped Radford University’s list of priorities. In addition, the university wished to maintain the aesthetic appeal and translucency of the structure’s previous air-supported roof, which was installed by Birdair in 1981 and outlasted its 20-year expected lifecycle by seven years. Birdair’s new TensothermTM with Nanogel® offered the perfect solution.

Developed by Birdair, Cabot Corporation and Geiger Engineers, Tensotherm consists of Cabot Corporation’s Nanogel aerogel sandwiched between two layers of structural PTFE fiberglass membrane. This creates an insulated, energy-efficient inner layer that maintains translucency and promotes natural daylighting. The fabric is less than 50mm thick, yet it more than quadruples the original roof’s thermal insulation performance with a value of R-12 and natural light transmission value of 3.5 percent. This durable, fade resistant material also offers maximum moisture control and superior sound insulation. These performance features are permanent, so they will not change over time.

“Projects like the Dedmon Center call for the beauty and durability of a fabric roof form, but also require a higher level of energy efficiency,” explains James Satterwhite, global daylighting business manager for Cabot Corporation, creators of the Nanogel aerogel insulation used in Tensotherm. “Options to create the balance between design and practicality remained a technical challenge until the advent of Tensotherm with Nanogel.”

By retaining cool air in warm conditions and warm air in cold conditions, Tensotherm with Nanogel meets increasingly demanding energy and building code requirements throughout North America. It can also contribute to LEED® certification, garnering credits in categories including insulation, green materials, innovation and daylighting. Nanogel aerogel is additionally Cradle to CradleTM certified.

Aesthetically, Tensotherm allows Dedmon Center to maintain the look of its previous air-supported roof. On the interior, the Tensotherm roof’s supporting steel truss system adds a new level of visual interest to the athletic structure.

“From the outside, the roof is very similar to what was there before,” explains Roy Saville, Radford University director of facilities planning and construction. “On the interior, the trusses now create a nice aesthetic with a unique focus.”

Functionally, the Tensotherm system will contribute significantly to overall cost savings in mechanical systems as well as long-term operational cost reductions due to increased efficiency. The material has additionally allowed the facility to incorporate air-conditioning, which had not been possible in the past.

“The new roof has many operational advantages,” continues Saville. “Our objective was to be able to air-condition Dedmon Center. The use of Tensotherm allowed us to meet our goal. Students, faculty, coaches and fans have all been very impressed.”

“Tensotherm now makes fabric membrane roofing a viable mainstream roofing option,” says Martin Augustyniak, Birdair director of operations and engineering. “The material’s ability to insulate like standard roofing while maintaining natural daylighting creates an unparalleled interior environment.”

Retrofit roofing construction on Dedmon Center began in May 2008 and was completed in January 2009. Birdair served as the project’s roofing contactor. The truss system was designed by Birdair in conjunction with Geiger Engineers and fabricated by Superior Steel of Knoxville, TN.