Bituminous Roofing System: Modified Bitumen (MB)

Celotex Roofing For Use In:
Bituminous System: Modified Bitumen (MB)

Modified Bitumen (MB) – Typically two layers of roofing membrane are laid down:  the bottom one has a smooth surface while the top one is embedded with a mineral surface, creating an effect similar to the multiple membranes of a built-up roof.

  • Asphalt sheet goods that have modifiers added to it to give it plastic or rubber-like properties
  • Two types of membranes
    • APP (Atactic Polypropylene) – typically heat-welded or torch-applied
    • SBS (Styrene Butadiene Styrene) – typically installed in hot mopping of asphalt or cold adhesive; some are self adhering
      • Have an adhesive backing
    • Surfacing includes aggregate, mineral, metal foil-laminate and smooth liquid-applied

Standard UL Class A/FM 1-90 Modified Bitumen System Cold/Hot Mopped

Modified Bitumen
  1. Metal deck
  2. 1 ½” rigid foam installation
  3. ½” Structodek® HD fiberboard roof board
  4. SBS, AP cold or hot mopped