A roofing base sheet is the first ply in a low-slope roof assembly, laid directly over the deck or over insulation before the ply sheets, modified bitumen cap sheet or torch-applied membrane goes down. It gives the rest of the assembly a uniform, asphalt-compatible surface to bond to and separates the finish plies from the substrate.

Base sheets are supplied in rolls and are either mechanically fastened with plates and nails or set in hot or cold adhesive, depending on the deck type and the membrane system being built up over them. Side and end laps are run per the membrane manufacturer's layout so that no fasteners or seams telegraph through the finished roof.

This roll is sold by coverage area rather than by length, which is the usual way base sheet and roll roofing are counted on a job \u2014 two squares of roof area per roll.

Key Features

• Roll coverage of 200 sq. ft., or two roofing squares
• Serves as the first ply of a built-up or modified bitumen low-slope roof assembly
• Asphaltic construction compatible with hot asphalt, cold adhesive and torch-applied cap sheets
• Can be mechanically fastened with nails and plates over nailable decks
• Provides a separation and bonding layer between the deck and the finish membrane
• Lapped side and end seams for continuous coverage across the roof field
• Rolled format unrolls flat for layout and cutting with a utility knife

Applications

• First ply over nailable decks in built-up roofing assemblies
• Base layer beneath modified bitumen cap sheets, torch- or mop-applied
• Low-slope roofs on residential porches, additions and flat-roof extensions
• Re-roofing over prepared existing low-slope substrates
• Deck separation layer beneath asphaltic membrane systems
• Small commercial flat roof sections and mechanical curbs

Product Details

• Type: Roofing base sheet
• Assembly Position: First ply / base layer
• Form: Roll
• Coverage: 200 sq. ft. (2 squares)
• Roof Slope: Low-slope
• Sold By: Each (roll)

1. Submit a quote request for this product
   
2. Our team reviews availability and pricing
   
3. We follow up with a detailed quote and next steps
   

Special order items are sourced to your project requirements. Pricing, availability, and lead times vary by product and quantity.

• Local pickup options available
• Delivery available depending on product and location
• Lead times vary based on availability and order size

Need Help?

Have questions or need help selecting the right materials?

Our team is happy to help.