After the storm
Wind damage
Wind does not push a roof down, it pulls it up. The first place it grabs is an edge, a corner or a loose flashing, and a small lift can become a torn roof in one gust.
- Edges and corners first
- Check after storms
- Do not wait for the next one
How wind damages a flat roof
Air flowing over a flat roof creates suction, strongest along the edges, at corners and around parapets. A membrane that is not firmly attached there flutters and lifts. Repeated flapping loosens fasteners, stretches the sheet and tears it at the weakest point.
Once water gets under a lifted edge, the problem is no longer only wind. The insulation gets wet, adhesive weakens and the next gust finds an easier job.
What storm damage looks like
Lifted or rolled-back edge
The membrane at the perimeter has peeled up and may be folded over itself.
Billowing or ripples
On mechanically fastened roofs, the sheet can balloon between fasteners. Ripples or raised areas show lost fastening.
Torn membrane or missing patches
A split along a seam, a rip near a unit, or debris puncture.
Displaced gravel or pavers
On ballasted and gravel roofs, stones pile up in one area and leave the membrane bare elsewhere.
Loose or bent metal
Edge metal, copings and counterflashings are bent or lifted, giving water a path in.
Debris on the roof
Branches, signs or rooftop items blown onto the membrane can puncture it.
Why Ontario roofs are exposed
Large, open roofs in plazas and industrial areas catch wind with nothing to break it. Tall condo buildings see stronger gusts at height. Summer thunderstorms bring short, violent gusts, and winter storms bring long, steady wind that drives snow and rain sideways into every gap.
Older roofs are the most vulnerable: adhesive has aged, fasteners have loosened, and the edge details were often built to older standards. A roof that held for fifteen years can fail in one storm if the edge was already tired.
What you can safely do afterwards
Check from the ground
Look for flapping membrane, loose metal and debris. Keep clear of the building edge in case metal falls.
Look inside
Check ceilings and walls under the roof edge for new stains.
Photograph for insurance
Take dated photos of damage before any temporary work. Contact your insurer about your own policy.
Stay off the roof
A damaged roof can be unstable underfoot and wind can return. Let a professional assess it.
How wind damage is repaired
Temporary protection
Tarps or temporary patches stop water getting in while the roof is dry enough to repair. Urgent leaks: mark the request as urgent and we answer those first. We do not promise a fixed arrival time.
Assess the attachment
We check whether the membrane, adhesive or fasteners lost grip, and how far along the edge the problem runs.
Re-attach or replace sections
Torn sections are cut out and replaced. Edges are re-bonded or re-fastened with more fasteners where needed.
Rebuild the edge
Copings and edge metal are refastened with continuous cleats so the perimeter holds under suction.
Typical costs
| Item | Starting price |
|---|---|
| Temporary leak protection (urgent call) | from $350 per visit |
| Small leak repair (patch, seam or puncture) | from $350 per repair |
| Flashing repair or replacement | from $500 per repair |
Starting prices in CAD before 13% HST, based on typical Ontario contractor rates (mostly Toronto and the GTA). The final price depends on roof size, access, the layers to remove, the membrane, drains and flashings, and is confirmed in your written quote.
Wind damage questions
Should I fix a small lifted edge right away?
Yes. A small lift is cheap to fix and the next gust will make it worse. Leaving it risks a large tear and wet insulation.
Does wind damage mean the whole roof is bad?
Not necessarily. Edge failures can be repaired and the perimeter strengthened. If the whole sheet is loose or the adhesive has failed, replacement is a better answer. See repair or replace.
Will gravel blow off a roof?
Loose gravel can shift in strong wind, especially near edges. If large bare patches appear, the membrane is exposed to sun and damage. Have it redistributed.
Leak, damage or an old flat roof?
Send a few details and photos. We reply by email with next steps and a written quote.