is a 60 mil self-adhering sheet membrane used for protection against roof leaks caused by water penetration from wind driven rain and water back-up caused by ice dams. This membrane is used in new construction and re-roofing beneath asphalt shingles, slate and tile. Granular Surfaced Roofing Underlayment is comprised of rubberized asphalt reinforced with a strong inorganic glass fiber mat.
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The top surface is imbedded with fine inorganic granules to provide a slip resistant surface. A scored siliconized plastic release liner is used to prevent the material from sticking together in the roll and is easily stripped away for installation.รก
The membrane adheres tenaciously
to the deck, permanently bonds to itself
at the laps and provides a seal around nails or other fasteners that penetrate the deck during installation of the primary roofing material.