Which installation characteristic is critical for modified bitumen roofing?

Proper flashing details are critical for modified bitumen roofing because they ensure that water is effectively diverted away from vulnerable areas, such as roof penetrations and transitions. Flashing serves as a protective barrier that prevents moisture from infiltrating the building envelope. In the context of modified bitumen roofing, which requires a reliable waterproofing layer, precise installation of flashing is essential to prevent leaks and prolong the lifespan of the roof.

While seams facing up the slope can also contribute to water management, they are not as fundamental as ensuring that flashing is installed correctly. Similarly, the pitch of the roof or the thickness of insulation layers play less of a pivotal role in the integrity of the roofing system compared to the proper execution of flashing. Thus, the emphasis on flashing details reflects its importance in maintaining the overall functionality and durability of modified bitumen roofing systems.