Heavy snowfall takes a toll on Chicago-area roofs — and collapses could be just the start of the misery

This year’s especially snowy winter is weighing on Chicagoans’ hearts, spirits and shoulders. But most of all, it’s weighing on their roofs.

At least eight buildings in the area have given way under the foot-plus of snow that has accumulated in recent days. The latest victims were a suburban horse training arena whose roof collapsed early Tuesday morning, though no people or animals were hurt, and three vacant buildings on Chicago’s South Side.

To an extent, it’s nothing but physics at work: Roofs are designed to handle a certain amount of weight, and if the snow grows too thick — it generally weighs about 20 pounds per cubic foot — something’s going to give.

But experts said plenty of other factors are usually at work, from the age and upkeep of the structure to the design of the roof itself.

Rod Petrick, past chairman of the Chicagoland Roofing Council trade group and president of Ridgeworth Roofing Company in Frankfort, said some of the buildings that had problems used “bowstring trusses,” which span the width of the building and don’t require center supports (warehouses and bowling alleys typically use this design).

“I’ve seen clients that have had a truss snap and it blows a hole in the wall,” he said.

Homes with pitched roofs have less to fear, he said.

“I would say 95% of residential properties are in good shape,” he said. “They should be fine.”

But residents like David Faris were taking no chances.

Faris, a politics professor at Roosevelt University, lives in Chicago’s West Ridge neighborhood, where the lake-effect snow has been particularly intense. After watching snow pile up on the flat roof of his bungalow’s sunroom, where his son’s playroom is located, a kind neighbor helped him remove it with a jury-rigged rake.

Now, after hearing from an insurance adjuster friend about a rash of garage collapses, he’s got one more chore.

”That’s another thing I’m worried about,” he said. “I’m going to try to take care of that tomorrow.”

Anatol Longinow, a professional engineer who teaches structural design at the Illinois Institute of Technology, said the recent snowfall hasn’t been especially waterlogged, so he didn’t see cause for alarm.

“From what I’ve seen, for a good home with a gabled roof, it’s usually not a problem,” he said.

But that assumes the roof is in good shape: He once discovered his own house had insufficient plywood beneath the shingles, he said, though he luckily had it fixed before winter arrived.

“If a snowstorm occurred, it could have broken that roof,” he said.

When it does happen, the damage can be immense: Morton Grove Fire Chief Frank Rodgers said the indoor riding arena at the Glen Grove Equestrian Center was “a total loss” after the roof collapsed under the snow Tuesday.

But he cautioned homeowners and business owners concerned about their own roofs to use sound judgment.

“It’s not safe to get up on a roof right now,” Rodgers said.

He said snow-related roof collapses in his area are a rare phenomenon — the last major one happened about 35 years ago — but other winter-related building problems, from broken pipes to roof leaks, could become more evident as the temperature increases this week.

Those are also prime conditions for ice dams, said Joe Palumbo of the company Ice Dam Guys, which is based in Minnesota but works all over the northern part of the U.S.

The dams form when warm air from the attic melts the snow closest to the roof, only to freeze when it runs down to the unheated overhang. Water can back up behind the ice that forms, getting under the shingles and into the house.

“More people will always have problems when it warms up,” Palumbo said. “Right now, it’s been really cold for quite some time. Business has been steady. Now, when we get up into the 20s and low 30s, oh my word. It just goes insane for maybe a week.”

His company uses superheated water to steam ice and snow from the roof, but he said snow rakes — long-handled gadgets designed to scoop snow away — are an effective preventive measure.

Petrick said water from a garden hose, which is usually in the mid-40s, can dissolve rooftop snow, as can nylon stockings filled with calcium chloride and tossed upon the roof. Like the other experts, though, he had a warning for overambitious do-it-yourselfers.

“If you’re not familiar with accessing a roof from a ladder, call a professional,” he said. “It’s dangerous when conditions are perfect, and conditions today are far from perfect.”

Chicago Tribune’s Madeline Buckley contributed.

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