Products / VaporDry SA Roof Underlayment

VaporDry SA is a vapor-permeable, self-adhered polypropylene trilaminate roof underlayment with a continuous, repositionable acrylic adhesive, approved for all roofing types at 3:12 or steeper and rated for a 250 degree F service temperature and 120 days of UV exposure. The physical properties sheet (revised 4/16/2026) prints 14 perms by ASTM E96, a 25-mil thickness, 4.75 by 80 foot rolls weighing 28 lb, a pass on ASTM D1970 nail sealing and AC48 water ponding, ASTM E84 flame spread 5 and smoke developed 15, and "Fire Tests of Roof Coverings ASTM E108 Pass Class A", and says it meets or exceeds the physical requirements of ASTM D226 (type II), D4869 and AC48. The product page says it "Meets ASTM D1970 testing standard for roofing underlayment", while the product data sheet and physical properties sheet tie D1970 to nail sealability only.