CertainTeed Flexiglas® Base Sheet is designed for use as a base sheet for hot asphalt applied, inorganic built-up or modified 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. Flexiglas Base Sheet will provide additional strength and improved handling and pliability 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. Also suitable as a mid-ply in multi-layer systems.

Technical Information

Non-oxidized (flux) asphalt, blended with a compatible elastomeric styrene-butadiene-styrene polymer and selected inert fillers.

  • Support Mat: Wet process fiber glass mat
  • Surfacing: Mineral release agent
  • Weight: 90 lbs. per roll
  • Dimensions: 39 - 3/8" x 98' 9" (324 square feet)
  • Coverage: Three Squares
  • Thickness: 1.2mm (48 mils)
  • ASTM D4601, Type II

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


CertainTeed Flexiglas® Base Sheet may be applied in hot asphalt or approved cold adhesives such as FlintBond®. Rolls should be stored upright, off the ground, and completely protected from the weather. Roof decks must be structurally sound, dry, smooth and meet or exceed minimum requirements of the deck manufacturer, local code and CertainTeed. Roof decks must provide positive drainage.

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

Warranty Details

CertainTeed backs its commercial roofing systems with the confidence of three warranty choices:

  • Limited Product Warranty
  • NDL Roof Membrane Limited Warranty*
  • Full System NDL Limited Warranty*

Owners and specifiers who choose the NDL or Full System NDL warranty options have the added security of manufacturer involvement in the sometimes difficult process of contractor qualifying and workmanship inspection. Consult with the roofing contractor and your CertainTeed commercial roofing territory manager to decide which CertainTeed warranty is best for your building or project.

*NDL warranties are not available on all specifications and are only available through CertainTeed Gold and Silver Star Contractors

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