How is modified bitumen built up roof applied in asphalt or bitumen modification processes?

Modified bitumen built-up roofs (MBBR) are applied using a multi-layer system that enhances durability and waterproofing. The process involves applying a base sheet, typically adhered with hot asphalt or cold adhesive, followed by multiple layers of modified bitumen membranes. These membranes are often heat-welded or mechanically fastened to ensure a secure bond. The modification process, using polymers like APP or SBS, improves flexibility and resistance to UV degradation, ensuring long-lasting performance in various weather conditions.