Modified Bitumen (or Mod Bit) is a type of membrane roofing system most often used for commercial buildings and tanks.  Furthermore, these structures typically have low-slope roofs and Mod Bit is a weather resistant product that will protect the substrate from leakage.  Obviously, the main purpose is to move water off the roof.  This product is an evolution of asphalt roofing.  Production  of the membrane uses asphalt and a variety of solvents and other rubber modifiers.  Application of the membrane to the roof uses either a hot or cold process.  When using heat, the objective is to seal the asphalt together by melting the edges of the membrane.  More recently, using cold-applied adhesives and self-adhesive membranes, it effectively seals out the elements.

The most common types of mod bit roofing are SBS and APP.  SBS refers to styrene-butadiene-styrene and its purpose in the product is to increase the flexibility of the membrane.  It also allows it to have stronger contraction and expansion capabilities as it’s exposed to differing temperatures.  Explaining further, the other acronym, APP, or attactic polypropylene increases the longevity of the roofing system.  Generally, the added flexibility is favored, so the SBS is the preferred solution because these additives increase the products flexibility.

Common Benefits of Mod Bit Roofing

• Factory manufactured rolls are easier to install and ensure quality control
• Weather resistant
• Easy to repair
• Flexible, expands and contracts
• Very durable

What is Bitumen?

It comes from crude oil refining or steel coking and is a thick oily byproduct of these processes.