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updated: 2/3/2011 8:41 PM

Be wary of post-storm risks

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  • Snow smothers the roof of this home on Golf Road in Libertyville after about 20 inches of snow fell in town during the Blizzard of 2011.

      Snow smothers the roof of this home on Golf Road in Libertyville after about 20 inches of snow fell in town during the Blizzard of 2011.
    Steve Lundy | Staff Photographer


The snow-blown landscape can present a pretty image but drifting on roofs is one of the potential concerns for homeowners in the aftermath of the Blizzard of 2011.

While there is no magic formula to determine how much is too much snow on your roof, there are some basic hints for homeowners.

"The long and short of it is it's not a good time to mess with the roof," said Bill McHugh, executive director of the Chicagoland Roofing Council and Chicago Roofing Contractors Association Chicago.

Tempting as it may be, professionals warn that homeowners shouldn't scurry up on the roof to remove drifts as doing so can cause more harm than good, to say nothing of personal safety.

The steeper a roof the easier it is to support snow loads, said Mike Atkinson, building commissioner in Vernon Hills although attention should be paid to valleys. Problems are more likely to occur on lower or flatter pitched roofs, he said.

"If you've got more than a couple of feet of snow on a flat or low-sloped roof, you should probably consider having it removed," he said.

Michael Prate, owner of Prate Installations in Wauconda and co-chairman of the roofing contractors association's committee that deals with single-family homes, said he already has received several such calls.

Homeowners can help themselves to a certain extent by using a telescoping snow rake, available at hardware or roofing supply stores, to remove what they can safely reach.

"If you've got a foot or more of snow at the bottom of the roof, if you have a rake available that would be advised," he said.

Removing the top layer will help and there is no need to get down to the shingles, he added, as that can cause damage and lead to leaks and other problems.

Getting excess snow away from the edge of the roof may help in the long run, however.

"Eventually, you'll get that melt cycle whether it's tomorrow or a week from now," Prate said. As air leaks into the attic from inside a home, it heats the roof deck and can prematurely melt snow, which can refreeze and create ice dams.

Those usually are at the gutter line, but ice can work its way beneath shingles farther up. If that happens, and how severe that might be, depends on several factors such as the age of the roofing material, whether an ice barrier has been installed and the type and amount of ventilation and insulation.

"It was a light snow, it blew off most roofs and most trees," said Bob Passmore, senior director of personal insurance lines for the Des Plaines-based Property Casualty Insurers Association of America, which has 1,000 member companies.

"I'm sure there will be some claims (relating to the storm) but I wouldn't expect a large influx," he said.

As for other storm impacts, Atkinson said, snow could have been driven into ridge vents.

"Go ahead and poke your head in the attic. If you see any snow in there, shovel it out," he advised.

He also said exhaust pipes for furnaces or water heaters that are not on the roof won't ventilate properly if they are blocked with snow, and could result in a carbon monoxide build up inside.

Passmore had some other common sense suggestions.

"Keep your downspouts clear. If you have window wells, if they're not covered, clear them away. Make sure your dryer vent is uncovered -- that can cause a lot of problems not the least of which is a fire," he said.