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Editorial: Beware of ice dams after major snowfall

With the recent heavy snowfall, it might be necessary to clean off the roof to prevent a cave-in or stop leaks into the attic that could wreck shingles.

The Minnesota Department of Commerce, Office of Energy Security reminds consumers that ice dams can lead to expensive repairs and hazards - and are frequently preventable. Ice dams are caused by the presence of warm air in the attic, combined with snow on the roof and the right weather conditions.

Ice dams occur when heat leaks into the attic and melts the underside of the snow on the roof. The melted snow then flows down the roof surface until it reaches a cold spot (such as the eaves or soffit) where it forms a frozen dam, behind which more snow melts and ice piles up. The ice build-up can back up under the shingles, damaging them and allowing water to leak to the ceilings and walls below.

To avoid these types of problems and eliminate most ice dams, attic air leaks must be sealed with caulking or expanding spray foam.

n Sealing attic air leaks saves energy and is key to preventing ice dams.

n An energy audit with an infrared scan can pinpoint trouble spots.

n If snow and ice must be removed, hiring licensed roofing contractors that use steamers is strongly recommended.

There are several things a person shouldn't do, however, including:

n Installing heating cables will shorten the life of your roof and cost you money to operate.

n Removing ice with shovels, chippers, chemicals, or heat can damage shingles, gutters, and other building components - and can be very dangerous.

n Adding roof vents - including powered vents - will not eliminate ice dams, and often makes the problems worse.

n Additional insulation - especially on the top plate of exterior walls - can reduce heat transfer to the roof deck, but insulation alone is insufficient. Typical attic insulation will not stop air leaks or prevent ice dams.

Most importantly, be careful if you will be working on your roof. Hire a professional if you are uncomfortable working on your roof.

For more information on ice dams and ways to conserve energy in your home, go to