The most technically challenging replacements are flat roofs. The aforementioned systems are rather straightforward, in comparison, with the execution of client preferences according to manufacturer’s specs and the Code. With flat, or low-slope, roofs we get into the wonderful world of design. Compatibility to connected systems, insulation configurations, drainage and durability are all considered in design specifications. There are dozens of low-slope systems available but this market has generally settled on two types of BUR (Built-up Roof) – fiberglass and modified bitumen