Unisil Fiber Bulking Agent


Unisil Fiber Bulking Agent is a soft, flexible high-tensile polyethylene fiber used as a general thickener to increase tensile strength and reduce sag for Unisil or Unisil HS silicone coatings.


Unisil Fiber Bulking Agent can be used to thicken silicone coatings into spray or brushable mastics. Thicker materials allow for fabrication of cants and filling around irregular surfaces. Excellent for flashing details, metal roof seams, inside and outside flashing details, round stacks, pipe legs, pitch pockets, conduit pipes, expansion joints, etc.

Unisil Fiber Bulking Agent allows you to greatly increase viscosity and filling ability of the coating at an economical price. Allows a higher viscosity and excellent vertical hold for a variety of applications. The unique nature of Unisil Fiber Bulking Agent’s configuration allows excellent melding to silicone, without allowing slipping. Adding Unisil Fiber Bulking Agent also creates a smooth, easy-to-apply material.

Sizes Available

1 gallon (3.8 liter) bucket
5 gallon (19 liter) pail


  • Retains elastic properties.
  • Increases tensile strength.
  • Improves bridging strength.
  • Fiber will not decompose.
  • Easily mixed with air operated mixers.

Physical Properties

Unisil Fiber Bulking Agent
Melting Point
~275ºF (135ºC)
Specific Gravity
0.965 g/cm3
Flash Point
665ºF (352ºC)
Moisture Content
< 2.0%
Fluffy fiber
Tensile Strength
228 lbF/in2


All documents are U.S. English unless otherwise noted

Commercial Roofing EagleView Commercial Property Owners Portal Architects And Specifiers


Product Princing and Where to Buy
© Copyright 2019 GAF | Privacy Policy and Legal | GAF Canada | GAF U.S.