Owens Corning WeatherLock Granulated Self-Sealing Rubberized Asphalt Roof Underlayment 36 in x 66.7 ft, 200 sq ft

Owens Corning WeatherLock Granulated Self-Sealing Rubberized Asphalt Roof Underlayment is a professional-grade roofing underlayment engineered to provide premium waterproof protection beneath asphalt shingles, wood shakes, and slate. Each 36 in × 66.7 ft roll covers 200 sq ft and is designed with a granulated, slip-resistant surface that resists tears and enhances installer traction and safety on the roof.

Because the underlayment is made from durable rubberized asphalt reinforced with a FIBERGLAS™ mat, it adheres tightly to roof decks and forms watertight seals around fasteners. The material does not wrinkle or absorb moisture like traditional felt and resists mold formation. WeatherLock G withstands UV exposure for up to 30 days, offering excellent performance in both hot and cold climates and effective protection against ice damming, wind-driven rain, and shingle blow-off.

WeatherLock G is lightweight and easy to handle, featuring a split-back poly release sheet for quick peel-and-stick installation. Its self-adhesive design helps ensure wrinkle-free application and long-lasting coverage—even before the top roofing material is installed.

• Roll size: 36 in W × 66.7 ft L (200 sq ft coverage)
• Rubberized asphalt material – Granulated, waterproof construction
• Slip-resistant surface for enhanced installation safety
• Reinforced with fiberglass mat for added tear resistance
• UV resistance for up to 30 days
• Ideal under asphalt shingles, wood shakes, and slate

Fast, contractor-friendly installation

WeatherLock G is engineered for easy handling and quick installation. The high-quality, self-adhesive material features a slip-resistant surface for added safety on the job site, allowing roofing professionals to work faster and with fewer complications. The split-back poly sheet peels away smoothly for easy positioning and wrinkle-free application. WeatherLock G is compatible with a wide variety of steep-slope roofing systems, making it a versatile and efficient choice for residential applications.

Durability in extreme conditions

WeatherLock G passes ASTM D1970 standards and is highly resistant to environmental extremes, including freezing temperatures, prolonged UV exposure, and wind-driven rain. Its rubberized asphalt construction remains flexible in the cold and tough in the heat, delivering long-lasting protection season after season.

Certified for performance

WeatherLock G is a trusted choice among roofing professionals, meeting key industry standards such as ASTM D1970, ASTM E108/UL 790 (Class A fire resistance under asphalt shingles), and Miami-Dade County product approval for severe weather regions.

Dimensions

Roll: 36 in × 66.7 ft