Key Takeaways
A roof that only leaks in some storms usually has a compromised flashing point or aging pipe boot, not a hole. Here's what causes intermittent leaks.
If your roof only leaks during certain storms — heavy rain with wind, but not the light rain last week — the cause is almost never a straightforward hole in the shingles. It's usually a marginal failure point, like a gap in flashing or a cracked pipe boot, that only lets water in when rain is driven at a specific angle by wind.
Why Does an Intermittent Leak Make Sense?
A roof sheds water efficiently when it falls straight down. Shingles, flashing, and underlayment are layered and overlapped to handle that. But when wind drives rain sideways or upward under an edge, it can find its way past a small gap that would never let water through under normal conditions. That's why a leak might show up during one wind-driven downpour and stay dry through several ordinary rains afterward.
What Usually Causes Wind-Driven Leaks
Aging Pipe Boots
The rubber or neoprene collar sealing a plumbing vent pipe hardens and cracks with UV and weather exposure years before the surrounding shingles wear out. A hairline crack in a pipe boot rarely leaks in light rain, but wind-driven water can push through the gap.
Step and Valley Flashing Gaps
Flashing around chimneys, walls, and roof valleys is designed to overlap shingle courses in a specific pattern. If a seam has separated slightly or a nail has backed out, it typically only becomes a leak path when wind forces water up and under the overlap rather than letting it run straight down.
Old Ice Dam Damage
If a section of decking or underlayment was saturated during a past ice dam, the wood or membrane underneath may still be compromised even after the ice is long gone. That damaged spot can reopen as a leak path under heavy, wind-driven rain even though it looks fine on the surface.
Isolated Leak or Sign of Something Bigger?
Most wind-driven leaks trace back to one specific failure point rather than a roof that's failing overall. A single isolated repair — resealing or replacing one pipe boot or a section of flashing — typically runs $150–$350. If a proper leak inspection finds multiple failure points or recurring damage across several seasons, that's a different situation: repeated small repairs can add up to $800–$2,000 over several years, and at that point it's worth evaluating the roof's overall condition rather than continuing to chase individual leaks.
Because the leak point isn't always obvious from the ground, the most reliable way to pin it down is a physical inspection during or right after a wind-driven rain, when the entry point is still visibly active. For a closer look at how our crew traces and repairs leaks like this, see our roof leak repair page, or check our flashing repair guide if you already suspect a flashing seam is the culprit.
What to Do If This Happens to You
- Note the wind direction during the storm when the leak occurred — it often points to which side of the roof to check first.
- Check the attic or ceiling below for staining even after the leak dries up; a return storm from the same direction will likely reactivate it.
- Don't wait for a "big" leak before calling — small wind-driven leaks left unaddressed are exactly what turns into the $800–$2,000 pattern of repeated repairs.
Naperville Roofing Crew has been diagnosing leak patterns like this across DuPage and Will County since 2005. Browse more repair guidance in our Roof Repair & Troubleshooting blog, including our breakdown of chimney flashing failures, a related and common wind-driven leak source.