Synthetic underlayments are growing in popularity among roofing contractors thanks to being lightweight and stronger than felt, but tests for ensuring they’re products that will perform as expected have been a bit lackluster.
That may all change soon, as ASTM International published its first U.S. product standard for synthetic underlayments, ASTM D8257, in December 2020, and roofing contractors wanting quality products should keep an eye out for compliant underlayments in the coming months.