In roofing, what is 'flashing' used for?

Flashing is a crucial roofing component specifically designed to direct water away from critical areas of the roof. It is typically made from metal or other waterproof materials and is installed at junctions, such as where different roofing surfaces meet, around chimneys, vents, and along roof edges. By effectively guiding water away from these vulnerable areas, flashing helps prevent water intrusion, which can lead to leaks and structural damage. This proactive measure in roofing design plays a significant role in maintaining the roof's integrity and prolonging its lifespan.

The other options do not align with the primary function of flashing; insulation, thermal performance, and providing a base for shingles involve different aspects of roofing construction and materials rather than the management of water drainage and protection.