High winds and hail: how to spot roof damage after a storm

A storm blows through in twenty minutes. The damage it leaves on a roof, though, sometimes waits three weeks to show up—as a brown stain on the bedroom ceiling. Wind and hail work quietly: from the sidewalk, the roof looks intact, while the waterproofing has already failed. Here’s how to read your roof after a severe storm, separate emergencies from the rest, and put together a clean file for your insurance company.

5 key points

1. Wind doesn’t just tear off shingles: it lifts the self-sealing strips that bond them together. A shingle that’s still in place may already have lost its watertight seal.
2. Hail mostly leaves impacts and granule loss. Those granules that build up at the bottom of the gutters are a warning sign, not a cosmetic detail.
3. A roof’s weak points during a storm are almost always the same: valleys, step flashing against walls and chimneys, ridge and hips, eaves/overhangs.
4. An active leak, a lifted membrane, or a section of roofing blown off are emergencies. The rest can wait for a full inspection—but not three months.
5. Take photos before doing anything, report the claim quickly to your insurer, and have temporary protection installed rather than a permanent repair until the file has been assessed.

What high winds really do to a roof covering

On a sloped roof, an asphalt shingle is held in place by two separate mechanisms. First, fasteners: the Quebec Construction Code requires at least 4 nails or staples per 1 m-wide shingle, installed 25 to 40 mm from the side edges and at least 12 mm above the cutouts (section 9.26.7.4.). Second, the sealing of the tabs, maintained by a mastic spot, an interlocking device, or a self-adhesive strip (section 9.26.7.5.).

A gust attacks the second mechanism before the first. It slips under the tab, lifts it, and the shingle starts flapping. Visually, nothing has moved. But the next wind-driven rain now gets under the course—and that’s how a roof that seemed unharmed after a storm starts leaking at the next downpour.

The areas wind hits first are predictable:

• Edges and the roof overhang. That’s where pressure is highest, and where the starter strip—nailed at intervals of no more than 300 mm on center (section 9.26.7.2.)—does its job.
• The ridge and hips. These shingles must overlap by at least 150 mm and cover the ridge by at least 100 mm on each side (section 9.26.7.6.). A ridge cap that’s twisted or lifted is easy to spot from the ground.
• Step flashing. Against a masonry wall or chimney, the counterflashing must be embedded at least 25 mm into the masonry and overlap the base flashing by at least 100 mm (section 9.26.4.4.). Counterflashing loosened by wind opens a direct path into the structure.
• Valleys. They concentrate water from two roof planes. The Code requires valley flashing installed over continuous support (section 9.26.4.3.), and storm debris that builds up there blocks water flow—a classic cause of leaks on steep-slope roofs, according to the ACEC roofing manual.

On a flat roof, the scenario changes shape but not logic. Wind looks for a poorly secured edge, gets under the membrane, and lifts it. Watch for openings along seams, wrinkles, and erosion that carries off gravel or the granular surface, leaving the membrane exposed.

Hail damage, more subtle than wind damage

Hail almost never punches a clean hole in a newer shingle. It does three things.

Granule loss. Granules protect the asphalt layer from UV rays. Where hail has knocked them off, the shingle ages faster. The best place to confirm this loss isn’t the roof—it’s the bottom of the downspout. A sudden buildup of fine gravel after a hailstorm says a lot about the extent of the damage.

Impacts. Small dark areas, soft to the touch, where the material has been bruised without puncturing. They’re counted per square meter, and that density changes everything in an insurance claim assessment.

Damage to sheet metal and accessories. Flashing, vent caps, gutters, chimney cladding. These are often what reveal how violent a storm really was, because metal keeps the impact marks while shingles absorb them.

Inspecting your roof after a storm without climbing on it

A visual inspection from the ground answers a big part of the question, and it’s infinitely safer. Walk around the house with binoculars or your phone camera on zoom, and look for:

• missing, curled, shifted shingles, or shingles whose line is no longer straight;
• twisted ridge caps;
• flashing that’s bent or pulled away from the wall or chimney;
• gutters that have come loose, are bent, or are full of granules;
• pieces of shingle or metal in the yard, which almost always indicates a bare spot on the roof;
• branches that have fallen onto the roof covering, which you shouldn’t pull off yourself.

Inside, the attic will tell you more than the surface. In clear weather, a point of light visible from the attic signals an opening. A musty smell, insulation that’s compressed or dark in one spot, a mark on the framing: these are signs of infiltration, even without a visible drip. After a winter windstorm, also check for blowing snow. Snow driven through attic vents isn’t a problem as long as it stays frozen, but it can cause serious damage when it melts.

What not to do: climb onto a roof that’s wet, icy, or covered in debris. Useful emergency actions can be done from inside—protecting belongings and, if needed, puncturing a bulging ceiling to channel water into a bucket rather than letting it spread.

Emergency or not? The distinction that costs you—or saves you

Three situations justify an immediate call to an emergency roofer:

1. An active leak. Water is coming in while it’s raining. Every hour worsens damage to insulation, drywall, and the structure.
2. A section of roofing blown off or a lifted membrane. The roof deck is directly exposed. A properly secured tarp or temporary membrane stops the bleeding before the next downpour.
3. Sagging, deck deformation, or a tree that has fallen onto the roof. The issue is no longer waterproofing but structure, and inspection must come before any roofing repair.

To address quickly, without being middle-of-the-night emergencies: a few shingles torn off on one slope, loosened flashing, gutters that have come loose, widespread granule loss. These won’t flood your basement this week. They shorten the roof’s service life and eventually open a leak at the worst time in winter.

Spot repair or full replacement: how to decide

The practical rule is distribution. Damage concentrated in one area, on a roof that’s otherwise in good shape, can be repaired: replace the affected shingles, redo the flashing, seal the valley. Damage scattered across all slopes, on a roof that already shows curled shingles or advanced granule loss, calls for a full replacement. The ACEC manual is clear on this: shingles that start to curl or lose their granules must be replaced, because curling acts like a dam and makes water run sideways.

The deciding factor is often age. On a roof near the end of its life, a post-storm repair is just patching around a bigger problem. An honest roofer will tell you that on site, with numbers to back it up, and with both scenarios.

Reporting to your insurance company

Order of operations matters more than speed.

1. Document before touching anything. Wide shots of each elevation, close-ups of affected areas, photos of the interior and the attic, photos of debris on the ground. Note the date and time of the storm, and keep the corresponding weather alert if Environment and Climate Change Canada issued one for your area (see the weather alerts published by the Government of Canada).
2. Report the claim without delay. Your home insurance contract requires notifying the insurer within a reasonable time. The insurer then assigns a claims adjuster, who works for them; you can, at your own expense, be accompanied by an independent adjuster.
3. Do the mitigation measures, not the permanent repairs. Installing temporary protection to keep water out is part of your obligations. Rebuilding an entire slope before the adjuster’s visit is not: you destroy the evidence of the damage.
4. Keep all invoices, including those for the emergency intervention.

What your policy covers depends on your contract, your coverages, and your deductible. Costs and timelines vary from one insurer to another, and the person who can answer that question is your property and casualty insurance representative—not your roofer. For the official steps after a loss, the Quebec government publishes a fact sheet on high winds detailing what to do before, during, and after.

One last reflex—and it avoids a lot of nasty surprises: before hiring anyone, confirm the contractor holds a valid licence in the Registre de la Régie du bâtiment du Québec. The days after a storm attract fly-by-night crews who knock on doors, take a deposit, and disappear.

Preventing damage from the next storm

• Have the roof inspected once a year, ideally in the fall, and have fasteners, flashing, and sealants corrected before wind season.
• Keep gutters and valleys free of debris so water drains instead of backing up under the shingles.
• Have branches that overhang the roof trimmed.
• Check attic ventilation: a roof that’s already baked all summer is less resistant to impact and uplift.
• Keep a photo file of your roof in good condition. It’s your point of comparison the day you need to prove that damage is truly attributable to the storm.

Frequently Asked Questions

How long after a storm does damage show up?

A clear leak appears during the event or in the hours that follow. A lifted seal or shifted flashing can stay quiet for weeks, until wind-driven rain comes from the right direction. That’s why you inspect after the storm—not only when it starts dripping.

How do you tell superficial damage from a structural problem?

Surface damage affects the covering: shingles, granules, flashing, gutters. It becomes structural when the roofline waves, the deck gives underfoot, attic insulation is soaked, or the framing shows water marks. The first can be repaired; the second requires an assessment before any roofing work.

Can I repair a few torn-off shingles myself?

Technically, a shingle can be replaced. In practice, the work is done on a sloped surface, often slippery, and a shingle that’s poorly nailed or poorly sealed recreates exactly the weakness the wind just exploited. The fall risk and loss of the manufacturer’s warranty outweigh the savings.

Can a roof be damaged by wind without any shingles blowing off?

Yes—and it’s the most common case. Wind lifts the sealing strip under the shingle tab. The shingle stays in place, but the watertight seal is lost. Only a close inspection reveals it.

Does hail damage a flat roof the same way as a sloped roof?

Differently. On a membrane, hail marks the surfacing, knocks off the granular protection, and weakens points already stressed by the sun. The consequences show mostly at seams, openings, and around penetrations, rather than across the membrane field.

Should I wait for the claims adjuster before having a tarp installed?

No. Protecting the building to prevent the damage from getting worse is part of your obligations. It’s the permanent repairs you’re better off postponing until the assessment, while keeping photos and invoices from the emergency intervention.

Is a post-storm inspection done in winter?

Yes, with caveats. Snow and ice hide part of the roof covering, so the inspection focuses on what’s accessible, the attic, and interior signs. Emergency measures can be done in any season.

What should I do if water is leaking inside in the middle of the night?

Shut off power to the affected room if water is approaching light fixtures or outlets, move belongings, contain the water, puncture the center of a bulging ceiling if needed to channel it into a bucket, and call an emergency roofing service. Don’t climb onto the roof in the dark.

Did a storm just pass through your area?

Urgence Toiture Montréal responds 24/7 across the Island of Montreal and surrounding areas for roof damage caused by wind, hail, and rain: emergency measures, inspection, a photo report for your insurance file, and a durable repair once the assessment is done.

Contact us to request a post-storm inspection by filling out the form. RBQ licence 5856-8684-01.