CertainTeed Glasbase Base Sheet is designed for use as a base sheet for both hot and cold applied, inorganic built-up roofing systems. It is suitable for use in the construction of various types of membranes for both new construction and reroofing, over a variety of substrates. Glasbase Base sheet will provide additional strength, moisture resistance and asphalt uniformity when used as the first ply over nailable, non-nailable and insulated substrates. In addition, it will perform as a venting base sheet when spot mopped over plastic foam type insulations.

Technical Information

CertainTeed Glasbase Base Sheet is manufactured on an extra strength fiberglass reinforced mat that receives a coating of weathering grade asphalt and is lightly surfaced with a mineral release agent. The fiberglass base mat provides excellent strength and moisture resistance. Glasbase Base Sheet is pliable and will confirm to most surfaces for easy of application.

  • Support Mat: Wet process fiber glass mat
  • Surfacing: Fine sand, release agent
  • Dimensions: 39-3/8" x 98' 9" (324 sq. ft.)
  • Coverage: Three Square
  • ASTM D4601, Type II
  • UL Type G2

For additional technical resources please refer to the CertainTeed Commercial Roof Systems Manual.


CertainTeed Glasbase Base Sheet may be applied in either hot asphalt or approved cold adhesive such as CertainTeed's FlintBond™, depending on system design and selection. Rolls should be stored upright, off ground, completely protected from the weather. Roof decks shall be structurally sound, dry, smooth and meet or exceed minimum requirements of the deck manufacturer, local code and CertainTeed.

For detailed installation instructions please refer to the CertainTeed Commercial Roof Systems Manual.

For Construction Details and Specs Click Here

Warranty Details

CertainTeed offers three asphaltic low-slope roof system warranty options: Limited Warranty on Materials, Integrity Roof System Limited Warranty, and Integrity Roof System No Dollar Limit (NDL) Limited Warranty. CertainTeed warranty durations are based on a combination of system specification and product selection. Please download an overview of these warranty options for details. Consult with your contractor or CertainTeed Territory Manager to determine which warranty is best for your project.     

CertainTeed offers standard asphaltic low-slope roof system warranty durations between ten and twenty-five years. Additionally, Gold Star Contractors can increase warranty durations by 25% by engaging in an Integrity Maintenance Agreement with their client.

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