What is the primary function of flashing in building construction?

Flashing is a critical component in building construction, primarily serving the function of creating a barrier against water infiltration. Its main purpose is to direct water away from vulnerable areas of the building, such as joints, seams, and intersecting materials, preventing moisture from penetrating into the structure. This is essential for maintaining the integrity of the building materials and safeguarding against potential water damage, mold, and deterioration over time.

In addition to its primary function, flashing can also play a role in enhancing the longevity of the structure by protecting areas like windows, doors, and roof edges from water. While other options may suggest additional benefits or purposes, the foremost function of flashing is undeniably to prevent water intrusion, ensuring that buildings remain dry and structurally sound.