Modified Bitumen (Mod-Bit or MB) is designed for buildings with a low-slope or flat roof structure and is used in installations like those of Built-Up Roofing (BUR) systems. While BUR systems’ layers are built on site, Mod-Bit is a roofing membrane that consists of plastic or rubber polymers and asphalt layers constructed at the manufacturer.

The most commonly installed Mod-Bit roofing system is Styrene-Butadiene-Styrene (SBS) which has superior flexibility for expansion and contraction. The other type of Mod-Bit roofing system is Atactic Polypropylene (APP) which has superior aging properties to SBS.

Modified Bitumen Roofing systems consist of five layers:

    1. Modified Base Sheets or Piles
    2. Modified Bitumen Membranes
    3. Insulation
    4. Adhesive
    5. UV protection and weather-resistant surfacing

Advantages of Mod-Bit to BUR include these:

    • Lighter weight
    • Does not require gravel/aggregate
    • Typically faster installation times
    • Light-colored surface reflects heat and cuts energy bills
    • Can handle wider temperature extremes
    • Factory-controlled manufactured membrane

View Other Types of Commercial Roofs