Gypsum wallboard is one of the unsung heroes of the architectural world. It's lightweight, easy to install, and adapts to almost any design. Best of all, it's economical. No wonder, then, that wallboard is used in almost all new construction single- and multifamily projects in this country.
Manufacturers have been moving beyond conventional wallboard in recent years, however. In fact, they've spent a considerable amount of time and resources developing specialty products that address application-specific problems drywall couldn't solve—moisture, mold, and noise chief among them.
By far, the most prominent of these problems are moisture and mold. Greenboard has long been a popular spec for moisture-prone rooms, and in the past, it had even been used as a backer board in wet areas. But in 2005, the International Code Council rescinded its approval of the material as a tile backer in wet areas. The code body now sanctions only cement- based backer boards and fiber-cement products, which aren't typically used for interior wallboard. In response, drywall manufacturers say they've developed moisture-resistant products that work well in moisture-prone areas.
“Wallboard companies have been heavily marketing products such as fiberglass-faced and paperless gypsum to reduce the chances of mold occurrences,” says Samantha Ciotti Falcone, AIA, a project manager with Althouse, Jaffe & Associates in Perkiomenville, Pa. She traces the flurry of new product development to a run of headline-grabbing mold problems at commercial properties in Florida and other humid climates. “Mold eats the cellulose found in paper-faced wallboards” and was found “growing behind the wallpaper” at several area hotels, she explains, adding that the problems were affecting “entire, relatively new facilities.” As mold madness began spreading among the general public and insurance companies, manufacturers saw a need in the residential market and responded accordingly.
“Since 2001, we've been promoting the message of managing mold and moisture through good design and construction practices,” says John Pappas, product marketing manager for drywall systems at Chicago-based USG Corp. Among its efforts, USG introduced a “high-performance” line of Sheetrock Mold Tough gypsum panels that look like regular wallboard, Pappas says, but have a treated gypsum core and a paper facing impregnated with a mold inhibitor.
Atlanta-based Georgia-Pacific Building Products' offering is DensArmor, a line of moisture- and mold-resistant products that use fiberglass rather than paper. “Paper facing in gypsum has a tendency to hold water” and provides a potential food source for mold, says Barry Reid, GP's product development marketing manager. “The glass-mat face and treated core [of GP's fiberglass alternatives] provide some forgiveness in wall assemblies.”