Unique Roof Glazing Offers Platform for Launch of New Technology

Aerogels help prefabricated roofing system deliver improved performance and aesthetics for new homes

Centerpoint Translucent Systems recently launched a line of unique prefabricated roofing products that could represent a whole new category within the fenestration market. Suitable for topping off roof sections in residential applications protruding from the main wall of a home—often in bay configurations—the products incorporate a high-tech, highly insulating aerogel glazing that delivers filtered natural light while keeping heating and cooling requirements to a minimum.

Because the glazed roofing products are prefabricated, installation is relatively simple and can save a builder considerable money and labor versus constructing a roof from materials used on the rest of the home, explains Kendall Sayer, president of the Knoxville, TN-based company. Ready-to-install roofs for bay windows and sunrooms eliminate about 50 man-hours and about $2,000 in materials based on the costs of framing, roofing and drywalling the typically small, awkward spaces, he continues. “The roofs come off the truck and are installed in as little as 10 minutes, providing a significant savings over the traditional shingle roofing of bay and dormer roofs in an entire subdivision.”

According to Sayers, the daylight-filled rooms that the roofing products create are popular with homebuyers and provide a unique selling point for builders. The popularity of the roofing products can be seen in the increased square-foot margin—about 10 percent—the company’s builder customers are seeing, he reports. In addition, builders are experiencing lower financing costs as homes with Centerpoint roofs spend less time on the market. Builders also report increased homeowner satisfaction and perceived quality of their homes. “Centerpoint translucent roofing systems simultaneously increase builder productivity and profitability,” Sayers states.

Centerpoint manufactures its line of products in sections at its plant in Knoxville, TN. The roof sections are manufactured, glazed and shipped to the distributor, where they are assembled into a complete unit delivered to the jobsite. Sayers and Mark Back, his co-developer, came up with the idea for these specialty roof units after some initial experience with translucent glazed roofing systems for the sunroom and conservatory market. Based on their experience, they knew that homeowners liked the natural light the available glazing materials offered, but were concerned about the potential for overheating. In developing the new roof products, they knew they had to overcome this challenge with some type of glazing material that could minimize heat buildup and generally offer a high level of energy efficiency.

Centerpoint launched its line with a translucent double-wall polycarbonate glazing material, but Sayers and Back were also looking for new alternatives. Their search led them to Europe, Sayers recalls, where they first encountered aerogel glazing technology in the architectural and commercial markets. Although manufactured in Europe, the supplier of the material turned out to be an American company, Boston-based Cabot Corp., a specialty chemical manufacturer.


Aerogel technology

Aerogels are highly porous silica materials that represent the lightest solid in the world, a fact that translates into high insulating values, says Jim Satterwhite, global business manager for Cabot’s Nanogel Construction Segment. His company’s Nanogel product is filled in the form of beads between two glazing sheets, providing the Centerpoint roof system with an R-value that is four to five times higher than the 1.5 R-value a typical skylight might have, he explains. The aerogel material is effective against both conductive and radiant heat transfer versus low-E glazings, which are only effective against radiant heat, he notes. In addition to a high level of energy efficiency, the aerogel technology enables the roof products to deliver superior acoustic performance, he adds.

Centerpoint continues to offer a number of glazing options for its roofing products. Currently three configurations of the new aerogel system are on display in model homes from Centex and D.R. Horton in South Carolina, with plans underway to install them in homes throughout the Southeast region. Sayers notes that homes featuring the new roof systems have received a warm reception from potential homebuyers and other builders.

“The product changes the way you think about construction,” says William Daniels of Covent Enterprises, a Knoxville builder. “This lets all the light in you could possibly want, without any of the downsides of that,” he explains, pointing to the high levels of heat that can be let in or out with windows and skylights, as well as the degradation of fabrics and materials that too much sun can cause.

A builder of upper-end spec and custom homes, Daniels notes he has long had a high level of interest in energy efficiency, but, he continues, the aesthetics of the product make the Centerpoint roofs particularly attractive. “There were two designers with me when I first saw the product. They don’t get excited easily, but when they saw it, one said ‘Wow;’ the other said ‘Oh my.’”

“The warm, soft light through this roof has to be seen to be believed, even on an overcast day,” says Dereck J. Lee, president, Advanced Builders, Myrtle Beach, SC. “As soon as people walk into houses with new Centerpoint roofs, they are drawn to the cozy, relaxing environments they create. Buyers are further pleased to learn that the Nanogel insulation can provide up to five times the energy efficiency of glass panels and can actually save them money by reducing heating and cooling costs.”

“Builders like these systems because they can actually save money,” Sayers concludes. “At the same time, they have something completely new to attract buyers. Homeowners love the daylight that these systems bring into a room.” As a result, Sayers is predicting that demand for the new roofing products will grow substantially.

  • Will Aerogels Become More Common in the Fenestration Market?

    The highly porous silica materials known as aerogels were first developed in the 1930s, reports Cabot’s Jim Satterwhite. Given their extremely light weight, the potential thermal performance benefits were understood early on, but manufacturing was a challenge, he notes. The available technology produced the material in very low volumes. It was also dangerous, which made it a very expensive proposition.

    A laboratory breakthrough occurred in the late 1980s that encouraged a number of companies, including Cabot, to further develop the manufacturing process. Cabot’s Nanogel product, introduced to the glazing market in 2001, consists of nanoporous particles with an air content of 97 percent, making the aerogel the lightest solid material in the world, Satterwhite states.

    Several manufacturers of commercial wall and roofing systems, including Kalwall Corp., are now using the material in translucent glazing applications. Since its launch, Cabot’s aerogel glazing products have been used in nearly 50 projects in North America and a dozen in Europe, with many more in the pipeline, Satterwhite reports. The primary demand to date has come from schools and institutional projects, where the systems have been used in both sloped and vertical applications. Similar to the Centerpoint roof products, the commercial glazing systems offer new design solutions for architects desiring both maximum natural daylight levels and energy efficiency, he states.

    The commercially available systems currently use polycarbonate and composite glazing materials in tandem with the aerogel. One step Satterwhite foresees hastening aerogels’ acceptance in the residential market is the development of an aerogel insulating glass unit. Research and development continues on such a product, and he suggests it will not be too long before an IG unit becomes commercially available.

    Other researchers have explored the possibility of developing aerogels that are clear, but Satterwhite sees that as an unlikely prospect. Although materials that can be seen through do exist, to date, they still remain visible and not particularly attractive, he reports.

    Satterwhite sees further applications for aerogel glazing in the residential fenestration market, however. The translucent nature of aerogels may limit their use in windows and doors, but he points to skylights, sunrooms and patio enclosure systems as logical applications. Vertical glazed areas combining clear glass windows with aerogel products also offer significant potential, he suggests, noting that his company has been in discussion with numerous window manufacturers interested in the technology.