Modified Bitumens were developed in Europe in the 1970's. Modifiers were added to replace the plasticizers that had been removed by advanced methods in the distillation process. The two most common modifiers are APP (attactic polypropylene) from Italy and SBS (styrene-butadiene-styrene)from France. The United States started developing modified bitumen compounds in the late 1970's and early 1980's. Mod Bit’s outperform the traditional Built-up Roofing. Mod Bit’s also use cold adhesives as well as hot asphalt products. These systems have warranties ranging from 5 to 30 years.