 Cold-applied adhesives and self-adhesive membranes are two of the more recent options.Copolymers commonly used to modify asphalt include atactic polypropylene (APP), styrene-butadiene-styrene (SBS), styrene-butadiene rubber (SBR), and styrene-ethylene-butylene-styrene (SEBS).These three application types of membrane roofing show distinct advantages over the previously more common flat roofing method of asphalt and gravel.