WOW-3639 (used in conjunction with EMC-3639) brings rainscreen drainage plane technology to our WEEP System, as part of an advanced design for creating division between the masonry and structural back-up walls. WOW-3639 consists of a 0.024″ (o.6 mm) thick high-impact polystyrene strip formed with 3/16″ (4.8 mm) deep corrugations, bent into an “L” shape with a 2.5″ (57 mm) leg and 5″ (127 mm) leg, both 2.5″ (57 mm) wide. This system is installed behind a thin veneer scratch coat and metal lath to create a system of tunnels and channels down behind and out of thin veneers at tops of wall openings (windows, doors, etc.) and must be used in conjunction with EMC-3639 for ensuring durability, rigidity, and longevity.