What is the purpose of flashing in building construction?

Flashing plays a critical role in building construction by serving as a protective barrier designed to prevent water intrusion. It is typically made of metal or other water-resistant materials and is strategically installed in areas where different building surfaces meet, such as at roof edges, chimneys, wall junctions, and around windows and doors. By redirecting water away from these vulnerable points, flashing helps to minimize the risk of moisture damage, which can lead to a range of issues including mold growth, structural deterioration, and damage to insulation and other building materials.

The effectiveness of flashing hinges on its proper installation and integration with the overall roofing and exterior drainage systems, making it an essential component for maintaining a building's longevity and integrity against the elements. This water management function is essential, especially in regions prone to heavy rain or snow, ensuring that the interior of the building remains dry and protected.