Tri-Flex 15 - Synthetic Roof Underlayment - 4' x 250' Roll

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Quick ID: Q26108
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Tri-Flex 15 is a synthetic roofing underlayment coated with polypropylene on both sides and offers many benefits to traditional #15 felt. This proprietary resin formula is used in the walk and deckside surfaces to create a slip resistant surface. It is 10x stronger than the #15 felt and prevents blow offs and tears in windy conditions. It is considered impermeable and will not allow water vapor to pass through it. A 10 square roll is 67 percent lighter than #15 felt, and covers 2.3 times the area. This sustainable product is 100% recyclable and contributes to sustainability and LEED. It exceeds the requirements of ASTM D226 type 1 and II.

Tri-Flex 15 is used with asphalt shingles or most other roof coverings as a secondary watershedding material. It may be exposed up to 60 days and can be used alone or in combination with Grace self adhered underlayments.


  • Synthetic replacement for #15 felt
  • Better coverage per roll and 10x stronger than traditional #15 felt underlayment
  • 100 % recyclable
  • Mechanically fastened with capped nails or staples
  • Available in 10 sq. rolls (48 in. wide x 250 ft. long)
  • Up to 60 days exposure
  • Meets ASTM D226, FBC, and AC-188 code standards


Manufacturer Part Number112737
Sub BrandGCP Applied Technologies
Code ApprovalAC-188 Acceptance Criteria for Roof Underlayments, Florida Building Code Requirements, ASTM E108/UL 790 for use in the installation of Class A asphalt glass fiber mat shingles and Class C asphalt organic felt or metal shingles, and meets ASTM D226 physical requirements of Type I and Type II
Coverage - Square Feet1000
Installation MethodMechanically fastened with capped nails or staples; Laid horizontally, starting at bottom of roof with print side up; Side laps must be minimum of 4 in. and end laps minimum of 6 in.
Installation Tools RequiredCapped nails or staples having 1-inch diameter plastic/metal caps - spaced at 8 in. OC on both side and end laps. High wind and coastal zones - double fastening to 4 in. OC; All cases - fasten at 24 in. OC down middle of roll in the field of the roof
Length - Feet250
Moisture Vapor Permeance0
Package Quantity1
Thickness - Inches7 mil
Warranty25 Year
Width - Inches48
Ships to HI/AKNo