Which application method is NOT commonly used for BUR systems?

The application method that is not commonly used for Built-Up Roofing (BUR) systems is spray application. BUR systems typically involve a layered approach using materials such as asphalt and fiberglass or organic felt, which are adhered together to create a waterproof membrane.

Hot mopping involves using heated asphalt to adhere the roofing materials, making it a traditional and widely accepted method for BUR applications. Cold adhesive application is also used for BUR systems, as it provides a safer and easier way to bond roofing materials without the need for heat, allowing for reliable waterproofing while being less hazardous. Modified bitumen application is common in BUR systems as well, often used for its ease of installation and versatile performance.

Spray application, although effective for other roofing types like single-ply systems or liquid-applied membranes, is not a standard method for BUR installations. This is due to the need for multiple layers and the specific material requirements of BUR systems, which do not lend themselves to the spray application technique typically used for other systems.