What is the main purpose of flashing on a roof?

The main purpose of flashing on a roof is to shed water onto roofing materials. Flashing is a thin material, typically made of metal, that is installed in areas where the roof meets a vertical surface, such as walls, chimneys, or vents. Its primary function is to direct water away from these critical areas to prevent leaks and water damage.

By allowing water to flow off the roof and directing it toward appropriate drainage areas, flashing helps maintain the integrity of the roofing system and extends its lifespan. Proper installation of flashing is crucial for effective water management, ensuring that water does not seep into the underlying structures and cause issues like mold, rot, or structural damage.

In contrast, other options either do not align with the primary roles of flashing or are irrelevant to the fundamental purpose of roofing systems. For example, while aesthetics may be a consideration in some architectural designs, the primary focus of flashing is functional rather than decorative. Similarly, flashing does not provide insulation or support weight; those functions are managed by different components of the roofing system, such as insulation materials or the structural framework of the roof itself.