Pecora ProPerm VP® is an integral part of the ProPerm vapor-permeable air barrier system. Pecora ProPerm VP® is a water-based, single component, primerless, elastomeric, cost effective, fluid-applied air barrier membrane for exterior wall assemblies where it functions as an air and moisture vapor retarder. Applied in a single coat this elastomeric weatherproofing membrane provides superior protection from moisture vapor and air intrusion contributing to a seamless, durable airtight building envelope.