CertainTeed Yosemite Venting Base Sheet is designed for use as a buffer sheet over existing roofing membranes in lieu of a divorcing layer of roof insulation on re-cover projects where the existing roofing membrane is left in place. It is suitable for use over existing gravel, mineral or smooth surfaced roof systems and is substituted for the base ply of the new membrane.

Technical Information

CertainTeed Yosemite Venting Base Sheet is manufactured on a heavy duty fiber glass mat which receives a heavy coating of weathering grade asphalt and is surfaced with mineral granules. The heavy asphalt coating provides excellent moisture resistance in conjunction with a durable, puncture resistant granule surface.

  • Support Mat: Fiber glass base mat
  • Top Surface: Sand
  • Back Surface: Mineral granules
  • Dimensions: 39-3/8" x 32' 10" ( 108 sq. ft.)
  • Coverage: One Square
  • Thickness: 2.8mm (110 mils)
  • ASTM D3909, D4897, Type II
  • UL Type G3

For additional technical resources please refer to the CertainTeed Commercial Roof Systems Manual or click on the Technical Information link located on the left navigation area.



CertainTeed Yosemite Venting Base Sheet may be applied in either a spot mopping of hot asphalt or with mechanical fasteners, depending on the type of existing membrane and substrate. The existing membrane surface must be prepared in accordance with CertainTeed's reroofing specifications prior to application of Yosemite Venting Base Sheet.

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

Warranty Details

CertainTeed offers four low-slope roof system warranty options: Limited Warranty on Materials, Limited Warranty on Systems, No Dollar Limit (NDL) Limited Warranty and Full System 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 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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