Wind-Driven Rain in the Quad Cities: Why Leaks Start at “Good” Roofs

One of the most frustrating things homeowners hear after a storm is: “But my roof was fine.” And they’re not wrong—many roofs are fine… until the Midwest delivers the exact combination that exposes a weak point: wind-driven rain.

Unlike steady rainfall, wind-driven rain pushes water sideways and upward. It finds edges, seams, transitions, and tiny gaps—especially around flashing. In Rock Island, Moline, Davenport, Bettendorf, and Milan, strong spring and summer storm fronts commonly produce the kind of wind that makes “small” vulnerabilities turn into active leaks.

What Is Wind-Driven Rain?

Wind-driven rain is rain propelled by gusts and pressure changes. It can:

• Push water under shingle edges

• Force water behind siding

• Overwhelm gutters and downspouts

• Exploit small flashing separations

That’s why leaks often happen during storms, not during normal rain.

Where Wind-Driven Rain Causes the Most Problems

Roof-to-wall intersections

These are prime leak zones, especially where step flashing and siding meet.

Chimneys and sidewalls

Chimney flashing failures are common because:

• Metal expands/contracts

• Sealants age

• Mortar joints can crack

Valleys

Valleys collect high volumes of water. If debris builds up or metal is compromised, water can back up under shingles.

Roof penetrations

Plumbing vent boots and exhaust vents can crack, especially after Midwest temperature cycling.

Why “No Missing Shingles” Doesn’t Mean “No Damage”

Leaks often start without visible shingle loss. A roof can look intact but still have:

• Loose flashing

• Lifted shingle edges

• Cracked seals around penetrations

• Minor fastener failure

• Debris-caused water backup

The Timing Problem: Leaks That Come and Go

A homeowner may see a drip during one storm, then nothing for weeks. That doesn’t mean it fixed itself—wind direction and rain intensity change each event. Intermittent leaks often indicate:

• A flashing issue

• A valley problem

• A penetration seal failing

What to Do If You Notice a Leak During a Storm

Safe immediate steps

• Put a bucket down

• Move electronics and valuables

• Photograph the leak/stain

• Note the storm date/time

• Avoid climbing on the roof

Then schedule an inspection. The sooner the source is identified, the easier it is to prevent interior damage from spreading.

Why Local Inspections Matter After Storms

Midwest storms are unpredictable. A local contractor understands how wind direction, roof geometry, and common home styles interact. That experience helps find leak sources faster and repair them correctly.

Schedule a Free Storm Inspection

If you’ve had a leak during heavy wind-driven rain—or you just want to confirm your roof and flashing are storm-ready—Twin Bridge Roofing & Construction offers free, no-obligation inspections across the Quad Cities.

📞 Call or text 309-948-4126 to schedule your free inspection, or visit roofqc.com to request an appointment online.