How Storm Damage Can Affect Your Roof

Asphalt shingles are held down by nails and by a strip of sealant that bonds each course to the one below once the sun warms it. Wind lifts the shingle, breaks that bond, and drops it back into position.

Nothing looks different afterwards. The shingle is in place, the roof reads as intact, and the seal that was doing half the work of holding it down is gone. The next strong wind lifts it properly, usually taking neighbouring courses with it.

The only reliable way to find this is by hand, lifting shingles across the affected elevations to see whether they are still bonded. It is the single most-missed form of storm damage.

When a shingle folds back and is laid down again, it carries a crease across its width. The mat is fractured along that line even though the surface looks continuous.

Creased shingles crack along the crease within a season or two. They are damaged goods regardless of how they currently look.

Hail knocks granules away and fractures the mat underneath. The visible mark is a roughly circular patch; the diagnostic is that the spot feels soft when pressed, like a bruise on fruit.

Bruising does not leak immediately. It removes the granule protection and damages the mat, which accelerates aging considerably in the years that follow.

Soft metal is a useful indicator of hail size: dents on gutters, vent housings, fascia trim and downspouts show whether the hail was large enough to have affected the shingles.

Uplift pressure is not evenly distributed. It concentrates at the edges and corners of a roof — rake edges, eaves, hips and ridges. Ridge caps are frequently the first thing lost, and once they are gone the ridge line and any ridge vent are directly exposed.

One elevation usually takes the weather at a given property. Damage patterns tend to repeat on that same side storm after storm.

Falling limbs are the other major mechanism, particularly on streets with mature trees. A limb strike can puncture the covering, break sheathing, and occasionally damage framing beneath.

An apparently small hole in the surface can sit above a much larger area of broken decking, which is one reason walking a storm-damaged roof is genuinely hazardous.

Dated photographs, taken before any repair work: wide shots establishing which elevation is affected, close shots of representative damage, and images of any interior damage.

Photograph emergency protection before and after it goes on. Most policies expect reasonable steps to prevent further damage, and the record of having taken them matters.

Write down the date of the storm and what happened. Specific beats general when an adjuster is deciding whether damage was sudden or pre-existing.

Isolated damage on a sound roof is a repair. Widespread loss of sealant bond across an elevation is a different situation, because every unsealed shingle is a candidate for the next event and replacing them individually is neither practical nor durable.

Where a roof was already near the end of its service life, replacement is usually the honest recommendation. How a policy handles age and depreciation is a matter between the homeowner and the insurer, and any contractor predicting that outcome is guessing.