The #509 All Weather Modified Mastic is a heavy duty commercial - grade rubber modified mastic specifically designed to be applied by the professional roofer under all weather conditions, dry or wet. It will bond under water for temporary or permanent repairs and is specifically designed for use with modified bitumen membranes, base sheets and ply sheets. The modified properties provides excellent adhesion, elongation and recovery characteristics. It adheres to all surfaces wet or dry and can be used on all flashings, gutters, around skylights, crevices, seams, flashings and repairs on SBS modified membranes. #509 All Weather Modified Mastic is excellent for repairs on conventional Built Up Roofing membranes where substrate movement is expected to occur. It eliminates burn hazards associated with hot kettles and propane torches, and is ideal where their use is prohibited. This product is formulated for repairs and seams on SBS Asphalt Modified Roll Roofing Sheets. Easy spreading and application in all weather conditions. Specially formulated for anti-sag properties and will not crack under high heat conditions. Carefully mixed homogeneous blend of high-grade fibers, select asphalt, plasticizers, minerals, and aromatic hydrocarbons. Fortified with Power Gel Technology so it will remain highly resilient and durable through all seasons.