The DuPont Tyvek DrainVent Rainscreen is designed to create a 6mm (0.25 inch) space for water drainage and air movement behind exterior claddings. The company says DrainVent replaces the intervening layer required for stucco and stone cladding and prevents mortar or stucco infiltration with a layer of filter fabric. The material uses a honeycomb matrix to provide a drainable spacer and protect against exterior moisture damage. The material is designed to be easy to cut, roll tight against corners, and lay flat, says the manufacturer. We found a 4-foot-by-50-foot roll online for $188. dupont.com
