When installing wood shake shingles, standard 36-inch wide underlayment rolls can be cumbersome and inefficient. G.A.P. #30 Split Felt, distributed nationwide by A1A Wholesale Supply, is purposefully sized at 18 inches to act as a high-performance “interlayment.” In a shake roof assembly, this felt is woven between the courses of wood, providing a critical secondary water barrier that directs moisture back onto the surface of the shingles.

This product is manufactured to ASTM D 4869 Type 1 standards, ensuring it has the necessary asphalt saturation to resist the unique moisture challenges associated with wood roofing. The 18-inch width allows for faster installation and a cleaner finish at the hips, ridges, and valleys. It is a rugged, reliable foundation that helps prevent wind-driven rain and snow from reaching the roof deck through the gaps in the wood shakes.

Product Details

• Manufacturer: G.A.P. Roofing, Inc.

• Material: Asphalt-saturated organic felt.

• Classification: ASTM D 4869 Type 1.

• Roll Width: 18 inches (Split Roll).

• Coverage: 108 sq. ft. (1 Square) per roll.

• Weight: 17 lbs per roll.

• Logistics: 60 rolls per pallet / 44 pallets per truckload.

Features & Benefits

• Optimized for Wood Shakes: The 18-inch width is the industry standard for shake interlayment, reducing material waste and labor time.

• Superior Moisture Defense: Provides a thick, asphalt-rich layer between shingles to shield the deck from wind-driven rain and ice.

• Ease of Handling: At only 17 lbs per roll, it is easy to maneuver on steep slopes and scaffolding during wood roofing applications.

• Consistent Saturation: High-quality organic felt ensures uniform asphalt absorption for a reliable, long-lasting barrier.

• Professional Grade: Specifically engineered for high-end cedar shake and wood shingle projects where a 30# class protection is required.

Applications

• Wood Shake Interlayment: Woven between courses of wood shakes to provide tiered water shedding.

• Hip & Ridge Protection: Sized perfectly for capping wood roof details.

• Valley Linings: Can be used as a secondary liner in narrow roof transitions.

• Repairs & Maintenance: Ideal for patching and upgrading existing wood shingle systems.

Technical Specifications & Logistics