What is the role of backer flashing in roofing?

Backer flashing plays a crucial role in roofing systems by ensuring a waterproof transition between different materials or components of the roofing structure. Its primary function is to direct water away from seams and joints where different surfaces meet, such as where the roof meets walls or around penetrations like chimneys and vents. This helps to prevent water intrusion, which can lead to leaks and damage within the roofing system and underlying structures.

In situations where other materials intersect, the backer flashing serves as an additional barrier that directs water to flow over the roofing surfaces instead of seeping through gaps. This characteristic is particularly important in maintaining the integrity and longevity of a roof.

Other choices, such as reflecting sunlight, insulating the roof, or enhancing aesthetic appeal, do not accurately describe the function of backer flashing. While these aspects may be influenced by other roofing materials or elements, they are not the primary roles of backer flashing in a roofing system.