APP roofing membranes are self-adhering using a roofing torch.  SBS roofing membranes are normally applied using hot asphalt or cold modified bitumen adhesive. Self-adhering SBS membranes and "hybrid" systems using a comination of SBS, APP and traditional asphalt products are also available.  What results are Built-up Roof Systems with enhanced performance and longevity.  All of these are good choices for industrial, commercial and residential low slope roofing.  Site access, structural load, appearance, warranty and performance must all be considered when choosing a specific system.