Figure 5: Six months of exposure to the winter weather in Maine resulted in virtually no effect to the fiberglass mat exterior sheathing used on these condominiums in 1984 to 1985.

Photo courtesy of Georgia-Pacific Gypsum

A quarter century ago, during a typically frigid winter on the seacoast of Maine, two partially completed structures weathered the storms and icy temperatures quite well.

And, much like the lighthouses that dot this craggy shoreline at the family resort of Old Orchard Beach, south of Portland, the buildings shone a light on something significant - in this case, the beginnings of a new way to construct commercial and residential properties.

Pat Huempfner proudly remembers that time, in late 1984. Then a just-hired sales representative for an engineered exterior gypsum product, he recalls that the two condominium projects-five- and seven-stories tall, respectively-were the first installations of a product that would revolutionize the construction industry: fiberglass mat exterior sheathing.

"Every gypsum company was looking for a way to avoid all of the issues related to paper-mold, moisture, warping and delamination," says Huempfner. But it was a concerted research and development effort that made the big breakthrough. Indeed, at testing laboratories on the opposite coast of the U.S., near Portland, OR, researchers had made a significant discovery. They invented a patented technology breakthrough whereby a gypsum core could be effectively wrapped in a fiberglass mat and embedded in the core, eliminating the need for gypsum panels with paper facing. Traditionally, gypsum panels were produced by encasing a slurry of calcined gypsum plaster with paper facings-so this new fiberglass-based method was a momentous innovation.

"By every indication, it looked like it would work great," recalls Huempfner. "But we needed to field test it to be sure." They teamed up with EIFS manufacturers who were quite understandably eager to find an improvement on traditional paper-faced gypsum sheathing. This was particularly vital in cold-weather environments, since the final coating on an EIFS system requires that the ambient temperature be above 40 degreesFahrenheit. "It was October, and the two under-construction projects on Old Orchard Beach would be exposed to cold weather for about six months, because it was too cold to finish the EIFS job," explains Huempfner. Two other condominium projects that were under construction stood nearby, which were also on hold for the winter. Those, however, had been built using paper-faced exterior sheathing. So, while field testing of the exposed fiberglass mat sheathing was going on, the opportunity emerged to compare its performance side-by-side with the technology it hoped to replace.

"We were going to get six months of snow, rain, ocean salt and wind-we couldn't have asked for a better test," emphasizes Huempfner. And as it turned out no one could have asked for more dramatic results. Despite bracing winds and sub-zero temperatures, the embedded fiberglass mat gypsum exterior sheathing performed impeccably on the two condominiums where it sat exposed. "Six months later, when winter was over and it was warm enough to finish the EIFS, these panels held up beautifully," says Huempfner. "Not one of them had to be replaced." And the other two under-construction condominiums, which had left paper-faced gypsum panels exposed to the harsh Maine winter? Over 50 percent of those panels had to be replaced, recalls Huempfner-and, of course, this time they used the new fiberglass mat sheathing.

Tom Remmele, now technical director for an EIFS manufacturer is also grateful for the groundbreaking work done to introduce fiberglass mat gypsum sheathing into the market as a substrate for EIFS."This was the first of its kind and really overcame the exposure limitations of ordinary paper-faced gypsum sheathing," says Remmele."The early work done to marry the sheathing with the EIFS products has now formed the basis for many years of successful installations.We continue to specify fiberglass mat gypsum today as a substrate for EIFS."

Ten years later, while on business in the area, Huempfner and a colleague returned to Old Orchard Beach to see how the condominiums that had first used this fiberglass mat sheathing were holding up. He was not surprised to learn that nothing had changed in a decade. "We spoke to one of the owners, and looked closely at the structures," he recalls. "The buildings looked great." Interestingly, they discovered that one of the structures had incurred some leaking in a carport ceiling, and that 3/8" holes had been drilled to allow the water to drain out sometime after the leak had occurred. "We thought it was amazing that the water build-up-over time-did not negatively impact the sheathing panel in that area," adds Huempfner."We call it 'moisture forgiveness'," he said, "because this substrate may give you enough wiggle room during the life of the building to survive this type of event."

"It was exciting to be at the forefront of something big," says Huempfner, "and to continue to see how well received these sheathings are-and how well they work-to this day." And while other companies have entered the fiberglass mat gypsum sheathing industry, Huempfner is quick to emphasize that it is the quarter-century legacy of innovation, field testing, experience and leadership-all of which crystallized during that frigid winter on the coast of Maine-that made the difference.

Faced with preventing moisture issues while keeping time sensitive projects in mind, Marriott International, Inc.'s design and construction team chose fiberglass mat gypsum panels for the Orlando, Florida-area hotel projects. The fiberglass mat gypsum panels not only mitigated the team's concerns with moisture management during construction, but they also saved significant time between closing for renovations and re-opening. The faster the projects are completed, the faster hotels can begin filling rooms with paying guests.

Among the first and most influential users of fiberglass mat exterior gypsum sheathing was Marriott, based in Bethesda, Maryland with more than 2,900 hotel properties in the United States and 67 other countries. Several dozen properties are in and around Orlando, and have included fiberglass mat gypsum products in the construction or renovation of multiple area hotels. Warren Neiman of Marriott who specializes in full-service domestic hotel renovation was an early advocate of fiberglass mat sheathing. According to Barry Reid, a product manager for sheathing products of this type, "We listened to what Warren Neiman had to say. Our best innovations and product extensions come from the design and contractor community. If they're having a problem, and they think it would be better for them if we customized an existing product a bit to solve it, we're always ready to listen." Neiman adds, "We want to maintain Marriott's high standards in all that we do, and that's what we look for in the products we use."

The hot and humid climate of the Orlando area can create moisture problems during and after construction. In Marriott hotel rooms, whose construction preceded the advent of the fiberglass mat gypsum panels, the moisture-laden air with air-conditioning units near windows gets trapped in wall cavities forming condensation. The mixture of moisture and condensation with paper-faced drywall creates a haven for mold growth. Marriott's design and construction team searched for solutions to moisture problems found in renovations and ways to eliminate the problem in new structures. The team's choice to use fiberglass mat gypsum panels was easy and quickly embraced because of its increased moisture and mold resistance over paper-faced options. Lengthy new construction cycles and renovation projects in the hospitality industry often fall victim to rain and other adverse weather conditions in such humid locales; therefore, fiberglass mat gypsum products have proven to be especially attractive over paper-faced alternatives. They are often backed by a limited warranty against delamination and deterioration for up to 12 months of exposure to normal weather conditions, but specific warranties should also be consulted for details. Further, the long-term mold risks are greatly reduced by eliminating the paper as food source for mold. This makes fiberglass mat gypsum products the best solution for both pre- and post-construction potential moisture and mold growth issues. Neiman, Marriott's full-service domestic hotels renovation specialist, estimates that the company does more than 200 renovation projects in the U.S. every year-including the remodeling of guest rooms, lobbies, restaurants and ballrooms, many of which specify only fiberglass mat gypsum sheathing and panels.

Marriott also recognizes that fiberglass mat gypsum products can accelerate the remodeling and construction process allowing quicker openings or re-openings of hotels. Marriott's construction and design teams were able to speed the construction and renovation process because fiberglass mat gypsum panels were also used on the interior of the building, allowing them to be installed earlier in the process, potentially allowing other trades to begin work sooner.  Reid notes  that the evolution and ongoing acceptance of fiberglass mat gypsum sheathing by the hospitality industry is simple to understand. "When you can show a property owner with high occupancy rates that his hotel will get built or remodeled faster and also last longer-the choice is simple."