WeatherLock® Flex


Helps Create a Water-Proof Barrier

Protects against water infiltration around eaves, rakes, valleys, vents, chimneys and skylights.

Helps Create a Water-Proof Barrier

Protects against water infiltration around eaves, rakes, valleys, vents, chimneys and skylights.


WeatherLock® Flex Flexible Self-Sealing Ice & Water Barrier provides excellent roof deck protection against water infiltration resulting from the freeze/thaw cycle, wind-driven rains and normal water flow around eaves, rakes, valleys, vents, chimneys and skylights.

Engineered for asphalt shingles, wood shakes and quarry slate roof assemblies, WeatherLock® Flex also offers:

  • High performance – Flexible and pliable poly surface and modified asphalt combine to adhere around irregular shapes, inside corners and at sharp angles, even in cold-weather applications to 40ºF
  • Added protection – Acts as a waterproof barrier in the most vulnerable sections of the roof, such as valleys and other roof penetrations, to create a second line of defense. For optimal protection, apply to entire roof deck on 2:12 to 4:12 pitch roofs*
  • Aggressive self-adhesive – Exceeds adhesion performance requirements to help prevent water migration
  • Slip-resistant surface – For excellent traction and safe installation
  • Seals tight around nails – Modified asphalt construction for a tight seal around nails to prevent water penetration
WeatherLock® Flex is an essential part of the Owens Corning® Total Protection Roofing System®^.

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Specifications and Literature

Product Information


SurfaceHigh-strength cross-laminated poly surface
AdhesiveModified Asphalt
Removable BackingPeel-away release liner
ApplicationEngineered for asphalt shingles, wood shake and quarry slate roof assemblies

Typical Values1

2.25 sq. roll
Length75ft. (22.8m.)
Width3ft. (0.9m.)
Gross Coverage225 sq. ft. (20.2 m2)

1. All values are approximate.

* Ensure proper ventilation is met when applied over the entire roof deck.

^ Excludes non–Owens Corning™ Roofing Products such as flashing, fasteners and wood decking.

UL Class A Fire Resistance applies when installed under asphalt shingles and quarry slate.

Applicable Standards & Approvals

  • ASTM D1970
  • UL ER19380-01
  • ASTM E108/UL 790, Class A Fire Resistance

Total Protection Roofing System®

Total Protection is more than shingle deep

It takes more than shingles to protect your home. It takes an integrated system of components and layers designed to help perform in three critical areas.

  • Seal Helps create a water-proof barrier
  • Defend Helps protect against nature's elements
  • Breathe For balanced attic ventilation

^ Excludes non-Owens Corning® roofing products such as flashing, fasteners and wood decking


Even though we’re a global company, we’re always ready to answer your questions. Call to speak with an Owens Corning representative so you can start your project right away.