What is the role of counter-flashing in wall structures?

Counter-flashing plays a crucial role in directing water away from wall structures, particularly where the wall intersects with other building elements like roofs or chimneys. Its primary function is to ensure that water that runs down the wall is redirected away from these junctions, preventing water infiltration that could lead to damage or deterioration over time.

When effectively installed, counter-flashing overlaps with the base flashing, creating a barrier that directs any water that penetrates the upper layers back out to the exterior, rather than allowing it to penetrate into the walls or the interior of the building. This is particularly important in areas that are vulnerable to moisture, as it helps maintain the integrity of the building materials and protects against issues such as mold, mildew, and structural weakening.

By focusing on this aspect of water management, counter-flashing significantly contributes to the longevity and durability of wall structures, highlighting its importance beyond mere aesthetics, insulation, or structural support.