WeatherMaster® Granular Surfaced Peel & Stick SBS Reinforced Underlayment

WeatherMaster® Granular Underlayment is designed for ice and water protection. It can go under any roofing material for maximum protection with the architectural design you are seeking. The composite underlayment is self-adhesive and reinforced with a fiberglass mat.

WeatherMaster® Granular helps protect the entire deck of a properly ventilated roof, especially those problem areas where water collects or drainage is slow. It provides a secondary layer of waterproofing protection needed to help prevent damage from ice dams and windblown rain.

The surface of opaque granules provides excellent traction and protection from UV radiation and weathering. This self-adhering modified bitumen underlayment creates a watertight barrier by sealing to the deck and around nails to provide continuous protection year after year.

synthetic underlayment


  • Skid Resistant for Better Traction And Safer Application
  • 40 MILS Thick, 15 MILS Above Industry Standard
  • 2x Stronger Adhesion Than Industry Standard - So It Stays Put!
  • Fiberglass Mat Provides Better Tear Resistance Than Saturated Felt
  • UV Protected Surface Allows For 45 Day Exposure
  • Provides Secondary Water Barrier

Installation For Roof Decks (Rakes and Eaves)

To begin, remove any dust, dirt, loose nails or other protrusions from the roof deck. Remove all shingles, roofing felt and nails from the deck of existing roofs. Sweep thoroughly to remove any dust and dirt. Apply WeatherMaster® Granular underlayment only in fair weather when air surface temperatures are above 45°F and rising. Apply to dry surfaces only.

Apply sheet parallel to the roof edge, extending over 1/4". Overlap edge seams 3", so that laps will shed water. End seams should be overlapped 6" and staggered. On steep slope applications it may be necessary to spot nail the top edge of the membrane temporarily during the installation process. For wrinkle-free application, cut WeatherMaster® Granular underlayment into 10 to 15 foot lengths and reroll.

Peel back 1 to 2 feet of release paper. Align the sheet on the lower edge of the roof and adhere the first 1 to 2 feet. Pull the release paper from under the sheet and continue to peel it while pressing the sheet into place. Roll lower edges firmly with a wallpaper roller or other hand roller. For ice dam protection, WeatherMaster® Granular underlayment must be applied to reach a point above the highest expected level of ice dams (minimum application at least to a height of 24" beyond the interior wall line). End laps should be overlapped 6" and staggered. When installing at temperatures below 45°F and on slopes above 8" in 12"—face nail in the overlap area at the top of the sheet at 12" OC. Priming the deck may be necessary below 45°F.

For Valleys and Ridges

Cut WeatherMaster® Granular underlayment into 4 to 6 foot lengths. Peel the release paper and center sheet over valley or ridge. Drape and press sheet into place, working from the center of the valley or ridge in each direction. For valleys, apply the sheet starting at the lowest point and work upward. WeatherMaster® Granular underlayment should not be left permanently exposed to the weather. It must be covered by shingles, metal valley flashing or other roofing materials within 45 days. Overlap horizontal overlaps at least 6" in valleys.Smooth shank galvanized nails are recommended for fastening shingles. Do not overdrive nails or break the surface.

Safety, Storage, and Handling

Pallets of WeatherMaster® Granular underlayment shall not be double stacked. Provide a weather cover on top and sides, allowing for adequate ventilation. Consult the Material Safety Data Sheet for best available information on safe handling, storage, personal protection, health and environmental considerations.