Modified Roofing (SBS and APP)

What is Modified Bitumen Roofing?

Modified Bitumen membrane roofing, an asphalt-based synthetic rubber composite material has been performing in commercial applications for over forty-five years. Modified bitumen membranes come in two forms: SBS, a synthetic rubber blend, and APP, a plastic blend. APP and SBS have different advantages, which we discuss in the next section.

Modified bitumen membranes offer redundancy and puncture resistance, making them ideal for high value properties and key infrastructure.

The easier way of describing them is as a next-generation of built-up commercial roofing systems, best known for their increased flexibility, high puncture resistance, weather and waterproofing, and strong resistance to foot traffic.

This has been a reliable solution for over 50 years and, like other options, has 20+ year manufacturer material and labor warranties available.

Benefits

Modified Bitumen roofing systems are in the asphalt family of roofing that have been modified with polymers (rubber or plastic) to increase flexibility and elongation.
Styrene Butadiene Styrene (SBS) is rubber based and Atactic Polypropylene (APP) is
plastic based
40+ year track record
Multiple layers of protection reduces leaks
Strong weather resistance and UV protection
Easily installed and repaired
Protection from wind uplift
Multiple installation options including hot asphalt applied, cold process applied, torch applied, and self-adhered.
20+ year warranted roof systems available

How are Modified Roofs Installed?

Modified bitumen membrane roofs are installed in a number of configurations. Generally speaking, they are installed as either conventional systems – where the membrane is installed on the top side of the system, to protected membrane assemblies (PMA) or IRMA’s (inverted roof membrane assemblies), where the membrane is installed on the bottom of the system, with some form of overburden installed over top.

Almost all modified bitumen membrane roofs in the commercial roofing space today are constructed with a form of adhesive, whether it be hot, cold, or torch-applied.

Hot applied systems are installed with hot asphalt, heated from a piece of equipment on the ground and piped up to the roof level. The hot asphalt is mopped out and the modified membrane is set into this hot asphalt, providing the bond.

Cold-applied systems are adhered with (usually asphalt-based) adhesive that is applied with a trowel or squeegee. Cold applied systems remove the need for a hot asphalt kettle or an open flame on the job site.

Torch-applied systems are installed with the use of a propane torch, where the asphalt is pre-coated on the roll. The roll is heated with the torch to a specific temperature in which the asphalt on the roll becomes sufficiently soft, providing adhesion.