What is the primary purpose of metal flashing in a building?

Metal flashing is a critical component in building construction primarily designed to prevent moisture entry. Its fundamental role is to channel water away from vulnerable areas such as roof joints, chimneys, windows, and door openings. By doing so, it effectively safeguards against water intrusion that can lead to significant issues like mold growth, wood rot, and structural deterioration over time. Flashing is usually installed at areas where different building materials meet, making it essential in waterproofing efforts.

While insulation, aesthetics, and structural support may play roles in a building's overall performance and design, they are not the principal functions of flashing. Flashing is specifically engineered to ensure a watertight seal, making it an indispensable element in construction and roofing. Thus, the primary purpose of metal flashing is to create a barrier that protects the building from moisture-related problems.