How is 2 ply modified bitumen roofing details applied in asphalt or bitumen modification processes?

2-ply modified bitumen roofing involves the application of two layers of modified bitumen sheets, typically using a torch-down or cold adhesive method. The first layer is installed with a staggered seam to enhance waterproofing, followed by a second layer that is either mechanically fastened or adhered. The modification process often includes the addition of polymers like APP or SBS to improve flexibility and durability. Proper surface preparation and temperature control during application are crucial for optimal adhesion and performance.