Modified Bitumen

Modified Bitumen, first introduced in 1978, was developed out of attempts to widen the serviceability range of conventional oxidized roofing asphalt. Increased resistance to brittleness at cold temperatures, greater flow resistance at high temperatures, and increased elasticity can be achieved by blending synthetic rubberized polymers with asphalt in lieu of modification by blowing processes (oxidation). The result is a membrane that combines the multi-layer benefits of a built-up roof with the installation advantages of a single-ply membrane. Modified Bitumen Membranes are manufactured with basically two formulas: Atactic Polypropylene (APP) and Styrene Butadiene Styrene (SBS). Both formulas are available with fiberglass reinforcement or polyester reinforcement. They are available in smooth surfaced or granulated rolls that can be heat welded, cold applied or hot applied.

Advantages of APP Modified Bitumen Membranes:

  • Can be cold applied or heat welded
  • Lightweight membrane; great for use as a recovery system
  • Because no aggregate surfacing is necessary, maintenance and repairs are easily accomplished

Advantages of SBS Modified Bitumen Membranes

  • High elongation properties makesSBS a good choice where building movement is expected
  • Excellent cold weather flexibility
  • Lightweight membrane; great for use as a recover system
  • Because no aggregate surfacing is necessary, maintenance and repairs are easily accomplished
  • Can be heat welded, cold or hot applied

Advantages of Fiberglass Reinforced Modified Bitumen Membranes

  • High tensile strength
  • Excellent fire resistance

Advantages of Polyester Reinforced Modified Bitumen Membranes

  • Excellent elongation
  • Excellent puncture and tear resistance