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The Styrofoam SIS structural insulated sheathing from Dow combines three functions in one product: structural lateral bracing and transverse loads, good insulation performance, and a water-resistive barrier. It offers a high R-value (R-3 at 0.5 inch; R-5.5 at 1 inch), which in turn reduces energy consumption and greenhouse gas emissions. The system also resists moisture intrusion and air infiltration; reduces installation time, labor, and material; and eliminates the need for wood structural panels and housewrap.

Editors’ Comments: We continue to see innovation in the area of the building envelope. By combining multiple functions, builders and remodelers can save on labor and material and minimize waste, while offering enhanced weathertightness and energy efficiency.