Synthetic Underlayment

Owens Corning® has been innovating the roofing industry with its technology for 40 years. After spearheading the effort with ASTM for several years, Owens Corning was successful in developing an industry standard that stipulates the performance requirements for synthetic underlayments.

When synthetic underlayments were introduced in the market, there was not a standard test method for determining their suitability as a roofing underlayment. Therefore, these products were tested in accordance with the long-standing standards for asphalt felt underlayments. These standards were primarily composition driven, and since synthetic underlayments are without asphalt, there are very few performance requirements in these standards that translate to the testing of synthetic underlayments.

ASTM D8257 has been established for the sole purpose of determining suitability of synthetic underlayment product for use as steep-slope roofing underlayments. This new standard includes many tests and a level of performance that applies specifically to this category of products, much more so than the older felt standards.

The ASTM D8257 testing requirements for synthetic underlayments are much more stringent than any previous mechanically fastened underlayment standard. All synthetic underlayments manufactured by Owens Corning meet the requirements of the new standard. The next step is ensuring that the new standard is included in upcoming building code editions. Owens Corning has already started the process of proposing that ASTM D8257 be incorporated into the 2024 I-Codes and the 2023 Florida Building Code. This will ensure products that don’t meet the stringent requirements of the new standard are not code compliant.