About LIBERTY™ Self‑Adhering Base/Ply Sheet

LIBERTY™ SBS Self-Adhering Roofing Systems are applied without torches, open flames, or hot asphalt, and are suitable for many primed substrates. LIBERTY™ Self-Adhering Base/Ply Sheet is a self-adhering modified bitumen roofing membrane intended to be used as either a base sheet for LIBERTY™ Self-Adhering Cap Sheet or as a ply sheet in modified bitumen roofing systems, providing long-lasting protection on low-slope roofs.

  • Convenient self-adhering installation eliminates open flames, hot asphalt, or dangerous chemicals on your roof
  • Reinforced with a glass mat which is coated with polymer-modified asphalt
  • Installed as a base sheet with LIBERTY™ Self-Adhering Cap Sheet or ply sheet for modified bitumen systems
  • Up to a 20-year limited warranty against manufacturing defects depending on system1


This product has earned the Good HouseKeeping Seal.


1See Limited Warranty on LIBERTY™ Self-Adhering Materials for complete coverage and restrictions.

Key Benefits

Serves as a Base Sheet for LIBERTY™ Self-Adhering Cap Sheet or Ply Sheet for modified bitumen roofing systems.

1See Limited Warranty on LIBERTY™ Self-Adhering Materials for complete coverage and restrictions

Thumbnail of video showing GAF LIBERTY™ Self-Adhering Roofing System step by step

LIBERTY™ step-by-step installation video

Step-by-step instructions show you how to install a LIBERTY™ low-slope roofing system.

Get automatic Lifetime Protection on your entire GAF roofing system

When you install any GAF Lifetime Shingle and at least 3 qualifying GAF accessories, you'll automatically get a Lifetime limited warranty on your shingles and all qualifying GAF accessories*.
*See GAF Shingle & Accessory Ltd. Warranty for complete coverage and restrictions. The word “Lifetime” refers to the length of coverage provided by the GAF Shingle & Accessory Ltd. Warranty, and means as long as the original individual owner(s) of a single-family detached residence [or the second owner(s) in certain circumstances] owns the property where the shingles and accessories are installed. For owners/structures not meeting the above criteria, Lifetime coverage is not applicable. Lifetime ltd. warranty on accessories requires the use of at least three qualifying GAF accessories and the use of Lifetime Shingles.

LIBERTY™ SBS Self-Adhering Roofing System Installation — Step-by-step*

  1. GAF roof contractor repairing damage

    Step 1

    Inspect the roof, and repair or replace damaged areas.
  2. GAF roofing contractors rolling on LIBERTY Asphalt Primer.

    Step 2

    Apply LIBERTY™ Asphalt Primer at a rate of a 1/2 gallon per 100 sq. ft.
  3. GAF contractors installing LIBERTY SBS Self-Adhering Base/Ply on flat roof.

    Optional (for 2-ply system):

    Install LIBERTY™ Self-Adhering Base/Ply.
  4. Contractor applying LIBERTY Flashing Cement on exposed roof flange.

    Step 3

    Install edge flashing at all eave and rake edges, and apply LIBERTY™ Flashing Cement on exposed flange.
  5. GAF roofing contractors installing LIBERTY SBS Self-Adhering Cap Sheet on a flat roof.

    Step 4

    Install LIBERTY™ Self-Adhering Cap Sheet.
  6. Finished flat residential roof with GAF LIBERTY system.

    Step 5

    Clean up by removing tools, unused materials, and other debris. Plan on inspecting roof annually if possible.

*See application instructions for complete details. 

Product Documentation

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