NEW ULM - The onslaught of snow that Minnesota has faced this month, with more projected for the weekend, emphasizes the importance of managing snow on roofs.
The common hazard to homes is the effect of ice dams on roofs. Ice dams occur when a large enough amount of snow creates blanket-like covering on top of a house. If the house has inadequate insulation or ventilation in its attic, heat will escape through the roof and melt the snow on it. Because there is so much snow on the roof, only the bottom melts and water attempts to run off the roof. Once it reaches the cooler area at the roof's edge, it will freeze into a solid ice barrier that typically can be seen by the icicles hanging from gutters. This process causes the water underneath the snow to become trapped and wreak havoc on the house.
"If you see icicles, it's a bad sign for your roof," said Jerry Sandmann, owner of Sandmann Roofing Systems.
This graphic illustrates the process by which ice dams are formed on the edges of roofs, creating potential for interior damage to homes.
Gargantuan icicles hang from the roof of this New Ulm home, possibly indicating a lack of attic insulation because the roof is clear of snow. / Staff photo by Josh Minoz
The heavy snow conditions this year have made it the prime environment for ice dams. In addition, the warm weather on Tuesday may exacerbate the problem because the thaw increased the amount of snow melt, but it did not last long enough to remove blockage. As a result, weather expected over the weekend could intensify the problem.
The consequences of not dealing with an ice dam cover a wide variety of damages, from general wear and tear to premature aging of shingles to water seeping into the house to gutter being torn off by the weight of the ice.
"Snow and ice on the roof can be dangerous," said New Ulm Building Inspector David Christian, "I was walking with the assistant city manager down a downtown alley and 6-footer icicle crashed down near us. If you got big icicles hanging on your house, try to get them off to be safe."
It is not advised to climb onto a roof to clear the snow if you are not a professional. The safest method to clear some of the snow is to use an snow rake to pull it off while standing on the ground.
"Never go on the roof unless you're a professional. It just isn't worth the risk," said Jerry Sandmann, owner of Sandmann Roofing Systems.
Other methods to remove the snow and ice are to have professional roofers do the job, use ice melt products to dissolve the ice or use a steamer to melt all the blockage.
Roofing contractors said steaming a roof is the best method to remove all of the snow and ice. The average price of having a steamer machine used on a roof can range from $300 to $800, depending on the house setup.
All of the roofing contractors questioned said preemptive measures are the best way to avoid ice dams.
"The one thing people need to be is proactive instead of reactive," said Dean Laraway, owner of Laraway Roofing, Inc., "By the time you see icicles, ice dams have already formed and you have hard work to do."
Suggested methods are to do preparatory work during the summer, such as improving attic insulation or installing heat strips. Efforts to do so in the winter will be significantly harder to perform and more expensive.
If weather has already left heavy amounts of snow on the roof, the best method is to clear off as much as possible with a snow rake. Removing a minimum of 6 to 8 feet is suggested to have any effect. Keeping roof vents clear of snow is also recommended. People who are unsure about what to do or if the ice is too severe to handle, contact a professional.
"When in doubt, call a professional. Advice is free," said Sandmann.
(Josh Moniz can be e-mailed at email@example.com)