What is the primary purpose of flashing in roofing?

The primary purpose of flashing in roofing is to prevent water infiltration at joints, seams, and penetrations. Flashing is typically made of metal or other waterproof materials and is installed in areas where the roof surface changes direction or where there are penetrations, such as vents, chimneys, or skylights. By directing water away from these vulnerable areas, flashing helps to ensure that water does not seep into the underlying structure, which could lead to damage and costly repairs.

Additionally, while enhancing the appearance and allowing for thermal expansion are important considerations in roofing, they are not the main function of flashing. The structural integrity of the roofing system is also important, but it is generally achieved through other components of the roofing installation rather than through the use of flashing. The focus of flashing is primarily on waterproofing, making option C the most accurate representation of its purpose.