ThermalTight combines a semi-vapor-permeable Neopor GPS rigid insulation panel with a vapor-permeable WRB laminated to the exterior face. The nonwoven, nonperforated polypropylene WRB extends 2 inches beyond the edges of the insulation panel on all four sides, resulting in flaps that are sealed with the manufacturer’s double-sided tape. This seal allows the WRB to function as a continuous air barrier as well as a water barrier. The 4-foot-wide ThermalTight panels are available in three thicknesses—1 1/16 inches (R5), 1 1/2 inches (R7), and 2 1/8 inches (R10)—and three lengths—8, 9, and 10 feet.