Styrofoam SIS

Styrofoam SIS—structural insulated sheathing—from Dow Building Solutions provides wraparound insulation, a water-resistant barrier and drainage plane, and structural shear bracing (replacing OSB, wood let-in bracing, or metal T-bracing) in a single panel. The closed-cell polyisocyanurate foam core is sandwiched between a water-resistive outer surface and a structural inner layer. A half-inch-thick, 4-by-8-inch sheet weighs less than 16 pounds.

These panels are available in 4-by-8, 9-, or 10-inch, in half- and one-inch thicknesses that respectively provide R-3 and R-5.5. To qualify as a water-resistive barrier, joints must be taped. Eighty percent postconsumer recycled content is claimed. Dow Chemical Co., Building Solutions; Midland, MI. www.styrofoam.com; 989-636-1000, 800-441-4369.