Whenever a building owner replaces a roof with either a rubber or PVC membrane, they frequently want the warranty that goes with it (assuming a qualified roofing contractor). If this is the case, the roofing inspector (from Firestone, Carlisle, or whomever else) can be your ally. My neighbor is one of these guys, and I've heard horror stories of what he's made roofers do to do the job right. Hope my two cents helps a little.
