Wind-driven rain leaks can be challenging for homeowners, as they can sometimes be trickier to diagnose and fix compared to leaks caused by gravity-fed rain. Here are some of the most common causes of these types of leaks:
Improper flashing: Flashing is the thin sheets of metal installed around roof penetrations like chimneys, vents, skylights, and valleys. These areas are particularly vulnerable to wind-driven rain, and if the flashing is not properly installed, sealed, or has deteriorated over time, water can sneak through the gaps and into your roof system.
Ice dams: In cold climates, ice dams can form at the edge of your roof where warm interior air meets the cold exterior. This melting and refreezing cycle can cause water to back up under the shingles and potentially leak into your attic or interior walls during wind-driven rain events.
Negative slope valleys:Â Valleys are the V-shaped dips where two roof sections meet. Ideally, these valleys should have a slight slope that channels water flow towards the gutters. However, if the valley is flat or slopes in the wrong direction (negative slope), water can pool in the valley, especially during wind-driven rain. This pooling water can then find its way under the shingles and leak into the roof.
Damaged roof membrane: Of course, the most obvious culprit could be a damaged roof membrane itself. Shingles that are cracked, missing, or have worn-down granules can allow wind-driven rain to penetrate directly through the roof deck.
Improper ventilation: While not directly causing leaks from wind-driven rain, inadequate attic ventilation can contribute to the problem. Poor ventilation can trap moisture in your attic, which can deteriorate roof components and make them more susceptible to leaks in general.
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