Millimeter-tall bumps on the surface of HydroGap Drainable Housewrap help create just enough of a gap to enable water to drain from wall assemblies at least twice as fast as other materials, the maker says. HydroGap is designed to remove 100 times more bulk water than standard housewrap and drains at 93%, meeting ASTM E2273, thus reducing the potential for moisture and mold damage in wall assemblies. Benjamin Obdyke | 800.346.7655 |