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Synthetic Roof Underlayments’ Continued Market Growth

Don’t let the underlayment be the weakest link in your roof system

Mcn Kyp Sharkskin Oct17 1
Mechanically fastened synthetic roof underlayments (SRUs) continue to take market share from traditional asphalt-based roofing felts/underlayments. SRUs were introduced to the North American market approximately 16 years ago. In general, SRU provide better ultraviolet (UV) resistance, performance and wind resistance. Installers realize reduced labor costs because the rolls are lighter, wider and faster to install.

Similar to many new product introductions, the market was slow to adopt SRUs. Slip resistance and uncertainties around product selection due to the differences in thickness and weight when compared to traditional ASTM D226 Type 30 felt and SBS roof underlayments were some of the causes of the initial hesitation.

Gradually, contractors and architects began to appreciate the many advantages provided by SRUs. Two of the driving forces were the reality that asphalt-based products were not performing as they had historically, while the price continued to climb. In general, many SRUs entered the market at a 30 percent price point over Type 30 felt. Today, many SRUs are cost competitive with asphaltbased roofing felts/underlayments in all categories.

The Right Choice

It’s important to choose the right SRU to fit the primary roofing system in which it’s installed. There is a wide variety of SRUs on the market today. Consider the applications: asphalt shingles, metal, slate and concrete/clay, etc., roofing products present

SRUs with different challenges regarding a wide range of varying conditions such as:

  • High temperatures beneath metal roof systems
  • Exposure time to UV
  • Abrasion resistance to foot traffic and roof debris in concrete/clay tile installations
  • Longer exposure fastener sealability before and after the primary roof is installed

SRUs designed to replace Type 15 felt should be used in the same applications where Type 15 asphalt felt has been traditionally used, under asphalt shingles. The Synthetic 15 type roof underlayment category does not provide the benefits of heavier SRUs. As an example a 10 SQ (1,000 square feet) roll of SRU can vary in weight from 23 pounds to 50 pounds.

Because of this large disparity in roll and per square weight, choosing the right SRU for the primary roof covering is of major consideration. SRUs that have been in the market for some time, have a proven track record are recommended choices of many installers. The lightest weight SRUs have become a commodity-based product category in many markets as distributors and contractors overly focus on price. Keeping things in perspective, the differences in price between lighter and heavier SRU is negligible in the overall cost of installing a roof, yet the performance comparisons can be vast.

Learn About Underlayments

ICC Evaluation Services AC188 acceptance criteria for roof underlayments is the standard to which most SRUs on the market are tested. The provisions of ICC-ES AC188 set a standard for performance, which is more intense than thresholds for Type 15 and Type 30 felts. It’s important to make sure the SRU you are using or considering meets these requirements. Learn more at

An ASTM subcommittee is working to develop a new standard for SRU. Whether the standard addresses only minimum requirements or establishes new thresholds for performance remains to be seen. In the meantime, the wide disparity in product weights and performance parameters, requires the installer to be diligent in choosing the right SRU for the job. To simplify, there are two main considerations: safety and ease of use for the installer, and the roof envelope system itself as a compilation of components that must match the performance parameters of the primary roof covering (same for wall envelope systems). Don’t let the underlayment be the weakest link in your roof system installations.

Mark C. Strait is president of Sharkskin Roof Underlayments, Simi Valley, Calif. To learn more, visit or call (805) 750-0084.