Modified bitumen is a roofing material that has become very popular in the last few years. It’s not only waterproof but also resists ultraviolet radiation, fire, heat, and other severe weather conditions. This membrane is made from asphalt with rubber modifiers added. One benefit of a modified bitumen roof is that it’s highly durable. However, replacement costs can exceed those for a traditional roof because the modified bitumen is more complex in structure, and the installation requires specialized labor.