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It's warmer out than it was a couple of weeks ago, and that's great, but this is Minnesota, so don't get used to it, plus have you seen your roof lately? Icicle city. That's what we get for wishing for warmer temps.

So what's happening?

It turns out that icicles are only part of the problem. If you see icicles, ice dams are likely on the roof, too, and they bring the potential for serious property damage. While the chance of being hit by an icicle falling off the roof is always a hazard, the more likely danger is to your house.


This year's heavy snowfall has created conditions for potential structural damage from melting snow on the roofs of buildings.

How ice dams form

1. Warm air rises through gaps, holes and other pathways into the attic.
2. The warmed roof melts the underside of the snow blanket.
3. Water from melted snow runs down and freezes at the roof overhang, causing an ice dam. Water trapped behind the dam seeps into the interior of the house from under the shingles.

Potential damage

4. Soaked insulation loses efficiency.
5. Damp wall cavities lead to rot and odor.
6. Interior walls can become stained and cracked.
7. Overhangs can become become wet and rot.
8. Siding can become stained and peel.
By Mark Boswell, Star Tribune

Ice dams form a ridge at the edge of roofs and prevent meltwater from running off. As pools of water back up behind the ice dams, the meltwater can work its way underneath the shingles. This is especially true if temperatures rise and fall above and below the freezing point, causing the water to melt and refreeze.

If water seeps into the roof, it can get to the framing or insulation of the house and cause mold and mildew to form, or with enough time, rot.

What to do about ice dams?

Remove snow from the roof if possible. This makes it less likely that meltwater will back up behind the ice dam. Roof rakes or brooms can work, but be careful about damaging the roof.

If it's an emergency because water is flowing into the house, the University of Minnesota Extension program recommends using a hose and tap water on a warm day to "cut" a channel in the ice dam, allowing any trapped water to flow off the roof. This might help for a few days, but if temperatures fall below freezing again, the ice dam will reform.

Dakota Weber with Urban Tree and Landscape sprayed snow and ice off the roof of St. Cecilia Catholic Church in St. Paul on Friday.
Dakota Weber with Urban Tree and Landscape sprayed snow and ice off the roof of St. Cecilia Catholic Church in St. Paul on Friday.

Shari L. Gross, Star Tribune

Is help available?

If professional help is required, people like Gabe Tschida of Urban Tree and Landscape will come in with a crew and heavy-duty equipment. Using lifts and a device that shoots low-pressure steam, the Urban Tree crew can safely get to your home's roofline and cut away the ice dams and icicles. A typical job takes about four hours at $400 an hour, said Tschida, but he knows of jobs that have ranged from $250 to $500.

How to prevent in the future?

A more permanent fix involves making the ceiling air tight so that warm air can't easily escape from the house and get into the attic. Complex roof designs, heating ducts, recessed lights and skylights often add to a building's ice dam problem.

Once air leaks are taken care of, added insulation can help as well. New construction should have a continuous air barrier through the ceiling to prevent air leakage.

To solve some of this, consider hiring an energy professional, like the folks at the Center for Energy and the Environment. Hire someone to conduct a blower test on your house to find out how airtight the ceiling is. Energy experts can use an infrared camera to search for areas of heat loss.