Ice dams a hot concern in snow-heavy Upper MidwestIce dams form when snow accumulates on a roof that's too warm, then melts and drains down to refreeze at the colder overhangs. That's when things get nasty. Water collecting behind the frozen dams may seep through the roof and down into the building, soaking the wall insulation or dripping straight through the ceiling.
By: Frederick Melo, St. Paul Pioneer Press / MCT
Mike Hilborn had four employees answering phones Wednesday, and they could barely keep up with the calls. The service he offers is to fix a problem most homeowners never think about: rooftop ice dams.
Hilborn, owner of Roof-to-Deck Restoration in St. Paul, said he's so busy this winter that he has brought in crews from his corporate offices in Chicago and Milwaukee to help eliminate the dams along eaves and gutters.
Ice dams form when snow accumulates on a roof that's too warm, then melts and drains down to refreeze at the colder overhangs.
That's when things get nasty.
Water collecting behind the frozen dams may seep through the roof and down into the building, soaking the wall insulation or dripping straight through the ceiling.
"Now you're talking mold problems and water damage," Hilborn said.
In previous years, he has seen chunks of ceiling collapse into a homeowner's kitchen. This week brought another kitchen disaster.
"This one lady, the paint was bubbling up inside her house, and the water was coming down through the ceiling and into her cupboards," Hilborn said.
Roof-to-Deck Restoration isn't alone in putting out the word about ice dams. The University of Minnesota Extension Service offers an Internet page on the mechanics of ice dams.
Many homeowners never have to deal with the problem because conditions must be just right for it to occur.
According to the Extension Service, portions of the roof's upper surface must average above 32 degrees for sustained periods of time while the lower surfaces average below freezing. The dams form in the areas that are below freezing, and water collects behind them in areas that are not.
The roof warms primarily because of heat loss from the house. Poorly insulated ceilings and inadequate attic ventilation are the main culprits, but chimneys, bathroom and kitchen exhaust systems and attic ducts that terminate just above the roof can cause problems, too.
Skylights and complex roof designs carry their own complications that can increase the odds of ice dams.
"A lot of people, this didn't happen to them last year," Hilborn said. "But that 17-inch snowfall (on Dec. 10-11), followed by very frigid temperatures, that is the recipe for creating ice dams. People will say, 'I've lived in my house for 10 years, and this has never happened to me before.' "
To prevent ice dams, the U's Extension Service recommends controlling heat loss from the house to the attic and removing snow from the roof.
But the latter can be precarious work in wintry conditions -- snow can be knocked off with a roof rake or broom, but homeowners should be careful not to slip off a ladder or damage the roof. The U's Extension Service recommends leaving that job to professionals.
Hacking away at an ice dam with a hammer or, worse, a chain saw is especially not recommended. That's a surefire way to damage the roof -- or hurt the homeowner.
Although enhancing ceiling insulation keeps heat out of the attic and prevents the roof from warming, it also means more snow can pile up. If the roof is built to code, it's probably able to withstand the snow accumulation. If it isn't, the accumulation could do damage unless it's removed.
Contractors such as Roof-to-Deck Restoration earn a living melting ice dams with specialized heating equipment, and Hilborn is the first to admit his service isn't cheap. He charges $290 an hour, with the typical St. Paul bungalow taking about two hours to treat, or twice that in bad weather.
On the web:
--The Minnesota Department of Commerce's Office of Energy Security has dedicated a Web page to ice dams. Visit www.state.mn.us and do a search for "ice dams."
--University of Minnesota Extension: extension.umn.edu/distribution/housingandclothing/DK1068.html
Distributed by McClatchy-Tribune Information Services.