As Canadians brace for another “flood season,” another water-related threat is already building overhead. Spring thaw is putting enormous stress on commercial roofs across the country – and when those roofs fail, the damage often goes far beyond a wet ceiling tile.
According to Jared Freeman (pictured), a risk management manager at Aviva Canada, water from above is one of the most persistent spring loss drivers.
“One of our leading loss drivers, based on the data we have, is water – overland water, water from roofs, water from piping,” Freeman said. “This time of year, you’re getting a lot of melt from the snow, so you already have a large volume of weight and capacity on your roof from water.”
The problem, he said, is that winter hides developing issues until the thaw exposes them.
“During the fall season, the leaves and debris are blowing around, then the snow comes and you get a freeze‑up,” he said. “You don’t have visibility because of the snow coverage, so you get all the surprises usually in the springtime.”
That makes early spring a prime time for losses – and, if handled properly, a prime time for prevention.
The way spring thaw affects roofs varies by region, building type and roof design. There is no single profile, Freeman stressed – but the mechanisms are consistent.
“Is there a perfect answer? No, because all those items – region, size, type of building – are variables we take into account,” he said.
In places like the Greater Toronto Area, repeated freeze–thaw cycles attack the integrity of flat roofs in particular.
“Picture a flat roof with a big membrane going across and then seams,” Freeman said. “If water penetrates into that seam, you can get what’s referred to as frost heave. As it freezes up at night, it can start popping your layers.”
On the West Coast, the concern is less about ice and more about volume.
“Out in Vancouver, you may get one of those atmospheric rivers that come in,” he said. “You want to know that your downspouts and scuppers on the roof are clear so they can handle this excess amount of volume during one of those large storms.”
Roof geometry matters just as much as weather. Flat roofs are more prone to ponding because they rely on slight pitches to draw water to drains. Highly pitched, architecturally complex roofs – such as those on high‑net‑worth homes – bring their own vulnerabilities.
“On large residential homes, with unique roof pitches and lots of dormers, what you can actually pick up is loose flashing, for example,” Freeman said. “That’s the metal directing water away from joints and vulnerable areas, to drive water down to a drain. If it’s loose or blocked, those areas become more vulnerable.”
Height differences between sections of the same building can also create dangerous “snow drift” zones.
“Think about a one‑storey office at the front of an industrial building and a 40‑foot roof deck over the manufacturing area at the back,” he said. “That step creates an area that will capture a lot of snow. That snow drift starts stressing your building in a different manner due to the excess weight, and most buildings are built to withstand certain things, not necessarily the extremes we’re starting to see.”
With natural catastrophe events becoming more frequent and intense, he added, “we’re getting surprises every year and they’re becoming more common.”
For many insureds, roof issues are still seen as a maintenance headache rather than a business‑critical threat. Freeman said that is a dangerous underestimation, particularly for manufacturers and food processors.
He gave the example of a generic 100,000‑square‑foot manufacturing facility with a one‑storey office up front and a high-roof deck over the plant.
“If that area goes into excessive snow load and the building is older or hasn’t been maintained, you start stressing all your structural members in ways they weren’t designed for,” he said. “If you get a roof collapse or a large water ingress, imagine you had production equipment underneath that.”
For a food manufacturer, the consequences are immediate.
“One of the governing bodies would come in straight away,” Freeman said. “Food is not going to mix well with rainwater. They would shut you down and you would have to correct that before you could get back up and running.”
Once the risk is understood, the next question is how to inspect safely and efficiently at the right times of year. That is where technology, including drones, becomes useful.
“What drones do is provide us, right off the bat, a safety benefit,” Freeman said. “Instead of a consultant or a client climbing up on the roof on a regular basis, we’re a lot safer on the ground behind a remote control flying a drone in an appropriate manner.”
In some facilities, simply accessing the roof is not possible without disrupting operations.
He pointed to a site in Quebec where industrial equipment on the roof made physical access impossible while the plant was running. In that case, a drone survey allowed the team to inspect the roof‑top machinery without shutting down production for a manual inspection.
Beyond flat industrial roofs, Freeman said the same approach is increasingly useful on renewable energy risks.
“We have a big renewable energy book,” he said. “On wind turbines, for example, after a large storm or lightning strike, you want to go up and see if there is delamination or burn patterns on blades that are 80 to 100 metres in length. A drone lets us take a look and provide a condition assessment to the client.”
In every case, the objective is the same: to put “eyes where you typically wouldn’t be able to put eyes,” identify problems exposed by spring thaw and extreme weather, and give businesses a chance to act before water from above turns into a costly shutdown below.
