The Invisible Storm Damage

After a serious Puget Sound windstorm, most homeowners walk outside, look up, see all their shingles still in place, and conclude they got lucky. Often they did. But the most common form of wind damage in this region leaves the roof looking completely untouched, and it does not announce itself for a year or more.

How a shingle is actually held down

Nails are only half the system. Every asphalt shingle carries a strip of thermally activated adhesive on its face. When the roof warms in the sun, that strip softens and bonds to the underside of the shingle above it, so each course is glued down along its leading edge as well as nailed at its head.

That adhesive bond is what stops wind getting under the tab. The nails resist the shingle being pulled off; the sealant strip stops it being lifted in the first place. Remove the seal and the nails are still holding, but the shingle can now flutter, and a fluttering shingle admits wind-driven rain underneath it.

What sustained wind does to it

Puget Sound storms are characteristically long. An atmospheric river system delivers hours of sustained wind rather than a few violent minutes, and that duration is exactly what breaks adhesive bonds.

Each gust flexes the shingle upward slightly and it settles back. Repeated across thousands of cycles, the bond fatigues and releases. The shingle then lies back down flat, because gravity and its own weight return it to position. From the ground — and frankly from a ladder — it looks identical to a properly sealed shingle.

It is not. It is now a flap held only at its head, and the next time wind and rain arrive together, water goes under it and onto the underlayment. Where the underlayment is sound, that may be tolerated for a while. Where it is old felt, wrinkled, or already compromised, the water reaches the deck.

Why this creates an insurance problem

This is the part worth understanding before it happens to you.

Homeowners policies cover sudden accidental damage from a covered peril such as wind. They exclude gradual deterioration, age, and wear. Broken sealant bonds are unambiguously storm damage — but they produce no symptom at the time.

So the sequence runs: storm in December, no visible damage, nothing reported. The following autumn, a slow leak appears in a ceiling. A contractor investigates and finds unsealed shingles across a slope. By that point, eleven months have passed, several storms have occurred, and establishing that a specific covered event caused it is considerably harder. The claim, if filed at all, looks like a maintenance issue.

Documentation contemporaneous with the storm is what prevents that, and it is why a post-storm inspection has value even when the roof appears fine.

How it is actually detected

There is no way to see this from the ground, and no clever trick. It requires physically lifting shingles by hand across the affected slopes and feeling whether the bond resists.

A properly sealed shingle resists lifting and will often tear rather than release cleanly. An unsealed one lifts freely with no resistance at all, and the difference is unmistakable once you have felt both. A competent inspection samples systematically across a slope rather than checking two shingles and generalising, because the damage pattern follows wind exposure and is rarely uniform.

Related findings from the same storm: creased tabs, where a shingle was folded back and returned, leaving a fracture line across the mat. A creased shingle is a failed shingle even though it is lying flat and looks fine. Missing ridge caps, which sit at the most exposed line on the roof. And granule loss in concentrated patches where a shingle was flexed repeatedly.

What can and cannot be done about it

Individual unsealed shingles can be hand-sealed with a small amount of appropriate adhesive under the tab. Done properly on a limited number of shingles, that is a legitimate repair.

It is not equivalent to the factory bond, though, and it is worth being honest about that. Hand sealing places adhesive where the installer puts it rather than in a continuous factory-applied line, and it does not restore the original wind rating. Where a large proportion of a slope has released, hand sealing dozens or hundreds of shingles is neither practical nor durable, and slope replacement becomes the realistic answer.

Prevention is a specification question at re-roof time. Shingles rated ASTM D7158 Class H carry stronger sealant and better lamination than lower-rated products, which is precisely what resists this failure. On exposed sites — the Sound-facing bluffs, ridgelines, anywhere with a long open fetch to the west — that is the correct specification rather than an upgrade.

The practical recommendation

After any storm severe enough that neighbours are finding debris or shingles in their yards, get the roof looked at, and get the findings documented in writing with dated photographs — even if, especially if, everything looks fine from the street.

If nothing is wrong, you have a dated record establishing the roof's condition immediately after a named weather event, which is useful later for entirely different reasons. If something is wrong, you have found it while it is a repair and while the causal link to a covered event is still straightforward to demonstrate.