Modified bitumen products have evolved to better meet the needs of today’s roofing contractor and building owner.
There have been a number of improvements to modified bitumen roofing systems, both in the way they are manufactured and applied, since they were introduced originally to this country. While modified bitumen products always have provided excellent handling and weathering characteristics by combining modifiers with high-quality asphalt and reinforcements of fiberglass, polyester or a combination of both, they have evolved to better meet the needs of today’s roofing contractor and building owner.
Initially, atactic polypropylene (APP) was the first modified bitumen product brought from Europe, finding great success in reroofing the cut-up, smaller buildings of the “torch-on” market of the Northeast coast. This was followed closely by styrene butadiene styrene (SBS) hot-mopped asphalt systems, which enjoyed success by ultimately capturing 50 percent of the overall market nationally. In addition to working as a roofing membrane system, both APP and SBS modified products also have been used successfully for many years as flashing for built-up roofing systems. As a membrane system, both APP and SBS products have had their shortcomings, which led to some of the more recent changes in the way they are applied.