Butyl Brush-Grade 320 is a single-component seam sealer specially formulated to provide a waterproof, weather-resistant membrane with excellent permeability and UV protection. Butyl Brush-Grade 320 offers excellent elongation and tensile strength to resist lateral movement and allow for daily expansion and contraction of the roof substrate. Butyl Brush-Grade 320 is specifically formulated to be less in viscous than Butyl Flashing-Grade 321.

  • Ideal for sealing holes, cracks and joints
  • Highly flexible
  • Superior elongation and tensile strength
  • Excellent elongation and tensile strength
  • Reduces daily expansion and contraction (thermal cycling) of roofing substrate

Butyl Brush-Grade 320 is recommended as a protective vapor barrier seam sealer for a variety of situations, including all types of seams, fasteners, gaps between metal panels, gutters, vent pipe flashings, air conditioning units and expansion joints. Ideal for metal roof applications with visible rust and all types of flat roofing substrates.

  • Metal
  • Modified Bitumen
  • Single-ply
  • Smooth BUR
  • 5-gallon pail
  • 2.5-gallon pail
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