StormStopper FSU™ earns high-temperature rating for 2026

By The Coffee Shops™.  

MFM Building Products expands its underlayment portfolio with a cost-effective membrane built for heat and moisture protection. 

As heat loads increase across steep-slope roofing assemblies, underlayment performance has become a critical factor in long-term durability. For contractors seeking a high-temperature rated solution that balances performance and price, MFM Building Products has expanded its lineup with an updated StormStopper FSU™ (Film Surface Underlayment), now rated for temperatures up to 240°F for 2026. 

Designed for use beneath asphalt shingles, shake and metal roofing systems, StormStopper FSU is a self-adhering film surface underlayment engineered to provide dependable secondary water protection. The membrane can be installed at eaves and valleys where ice dams and wind-driven rain pose the greatest risk, or across the entire roof deck for added leak defense. It also serves as a flashing membrane around penetrations, helping contractors create a more comprehensive waterproofing strategy. 

StormStopper FSU is composed of a polymer film with an embedded traction surface laminated to a high temperature rubberized asphalt adhesive. The adhesive bonds when surface and ambient temperatures reach 45° F or higher and seals tightly around common fasteners to reduce the risk of water intrusion. With a nominal thickness of 45 mils and a split release liner for efficient placement, the product is engineered for speed and ease of installation, particularly in valley applications. 

The underlayment may be left exposed for up to 30 days and carries a five-year limited warranty. It meets ASTM D 1970 and is approved under the Florida Building Code FL 11842.1, Miami-Dade County and the Texas Department of Insurance. It is also listed in the Fortified Building Program. 

Available in 36-inch by 67-foot rolls packaged as 30 cartons per pallet, StormStopper FSU offers an economical option for budget-conscious projects without sacrificing quality. The product joins the company’s other high-temperature rated membranes, including Wind & Water Seal, Ultra HT Wind & Water Seal and Premium HT Tile & Metal, further strengthening MFM Building Products’ portfolio for demanding roofing environments. 

Original article and photos source: MFM Building Products