A durable roofing system that has stood the test of time - modified bitumen roofing systems were first introduced in the mid 1960's and continue to be one of the most widely used low-slop roofing systems today.
First introduced in Europe in the mid 1960's, modified bitumen membranes are roofing sheets made of asphalt that has been modified with either rubber (SBS) or plastic (APP) to offer greater stretch and flexibility. Similar to BUR, modified bitumen is installed in multiple plies, typically 2-3. Torches are used to join material body and seams, creating a watertight system. Modified bitumen can also serve as the cap sheet of a BUR roofing system.
One of the biggest drawbacks to modified bitumen is that extreme heat is needed to properly weld sheet seams, unless using cold-process adhesives. Heat is typically applied with open-flame torches, but if not used properly, these flames can start fires on the roof and in the underlying structure.
Modified bitumen is an excellent commercial roofing system because it is resistant to heavy foot traffic, punctures, and tears. Featuring plastic- or rubber-based polymeric binders in its formulation, modified bitumen is flexible and expands or contracts with the building, making it suitable for many different climates.
One reason why modified bitumen is one of the most popular roofing systems is how easy and quick the installation process can be for an experienced production crew. A quicker roof installation often times results in reduced labor costs, potentially saving you thousands on your new roofing system.
Modified bitumen sheets are manufactured under tight quality control, resulting in consistent thickness. Manufacturers assemble the torch-preparation linings, waterproofing binder, weather-resistant surfacing, and fabric reinforcement into sheets with uniform physical properties and thickness. This consistency guarantees a reliable and proven performance from the product.
An often overlooked benefit of asphalt-based roofing systems, like modified bitumen, is their compatibility with off-the-shelf roof repair products. While most leaks require the expertise of a roofing professional, some can be repaired simply by applying a bit of roofing cement. Often times, building managers and owners fail to realize that asphaltic repair products, such as roofing cement, is incompatible and ineffective on modern single-ply roofs.