Roofers warn of a 'perfect storm for ice damming' as thaw leads to water damage in homes

Roofers in southwestern Ontario are trying to keep up with calls this week from homeowners experiencing major water damage as the snow and ice melts. 

The warmer weather in recent days has seen ice dams form on many roofs resulting in leaking ceilings and water running down walls. 

"This year has been a perfect storm for ice damming as we've had an extended period of cold weather coupled with a lot of snow," Todd McIntyre, who owns Byron Roofing Inc. in London, said.

Ice dams form when snow on a roof melts, either from hot air escaping a home or from the sun. When the water runs down the roof, it can re-freeze at the edges. As the process continues, an ice dam builds into a larger block that can lift the shingles. Eventually, when the ice melts, the water runs into the home.

"Typically, water is great coming out of a tap, but it's not so great coming out of light fixtures, down ceilings and walls, or that sort of thing," McIntyre said.

Murray Shaw Roofing, also in London, had more than 10 calls about the issue on Monday alone. That's when the sun  really showed itself after weeks of frigid weather, and temperatures reached upwards of 5 C. 

"There's been a lot of damage in the last week just because of the thaw," the company's operations manager Jessie Miller said. On one roof, he was tasked with breaking off 14 ft. icicles to access an ice dam. 

Older homes, roofers said, are more at risk of forming ice dams as they often have poor insulation and ventilation. By the time they form, it's often too late. 

Joan Barfoot, a homeowner in London's Old North neighbourhood, said an ice dam caused a small stream of water to trickle down her back doors for about four days last week.

"It just feels terrible, it's like your house is suddenly opposed to you," Barfoot said. 

Even more frustrating, Barfoot said, is that this isn't her first experience with ice dams on the roof. She had heating cables installed but plugged them in too late in the year, a mistake she said she won't make again. 

Other homeowners do remove snow from the roof with a shovel or an ice rake, but roofers caution that incorrect technique can be damaging. 

"In years past, the first rain storm in spring, we get calls about roof leaks from somebody who was up there removing ice with a pickaxe or hammer and they poked a hole in the roof," McIntyre said. "More often than not, you'll create a bigger problem than having a professional come do it."

Miller said homeowners should also think about safety, if they're considering climbing onto their roof.

"It's very slippery when it gets icy and wet – there's no traction," he said. "Just use a roof rake to try to get it from the ground." Alternatively, McIntyre said people can wait the leak out, letting snow melt naturally. 

Ice dams are nothing new, but roofers said Ontarians have forgotten about them as recent warmer winters have made them less frequent. 

"The last three or four winters have not had a lot of snow or cold weather, so that doesn't generate ice dams," McIntyre said. "The calls we're getting right now are similar to what we used to get during a normal winter."

Miller said Londoners should plan ahead to prevent ice dams before next winter, making sure they have proper insulation and exhaust fans. 

"The best solution is preventative maintenance," Miller said. "It's always best to be preventative as opposed to reactive."