Johns Manville JMCleanBond® SBS Base Sheet is a self-adhering, fire-resistant modified bitumen sheet incorporating the features of a fiber glass mat with a blend of SBS (Styrene-Butadiene-Styrene) rubber, fire-retardant additives and high-quality asphalt with full recovery properties after 100% elongation and lends elasticity and flexibility to the sheet. The modified asphalt is self-adhering and has an easy-to-peel, removable release plastic film on both sides of the sheet and the selvedge for ease of application.