Sealing modified bitumen roofs involves applying a layer of modified bitumen membrane, which is typically composed of asphalt modified with polymers for enhanced performance. The application process includes cleaning the substrate, heating the membrane to activate its adhesive properties, and then rolling it out onto the surface. The edges are often welded or sealed to ensure a watertight bond. This method enhances durability, flexibility, and resistance to environmental factors, ensuring long-lasting protection for the roofing system.