What does "re-roofing" involve in the context of BUR systems?

Re-roofing in the context of BUR (Built-Up Roofing) systems typically involves the installation of a new layer of BUR over an existing roof. This method is often used as a way to extend the life of the roofing system without the need for a complete tear-off. By adding an additional layer, the integrity and waterproofing of the roof can be enhanced while taking advantage of the structure already in place.

This approach can be efficient and cost-effective, allowing for less disruption to the building and minimizing waste associated with the complete removal of the existing roofing materials. New BUR layers are applied in the same manner as traditional BUR, utilizing layers of felt and bitumen but are dependent on the existing structure's capability to handle the additional weight and ensure compatibility with the existing materials.

The other options, such as removing the old roof entirely, replacing insulation, or retrofitting drainage systems, represent different procedures that may be necessary in specific situations but do not accurately define the standard re-roofing process within BUR systems.