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Preventing Ice Dams

Handy man mitigating ice damsWintertime icicles may look charming, but they usually signal a serious — and  potentially costly — problem. Often lurking behind that thick ridge of ice on  your roof is a pool of melted water, hence the term ice dam. That accumulated water can work its way under roof shingles and into the home, causing  significant damage to ceilings, walls, and floors. Additionally, the sheer  weight of the ice dam often causes gutters and downspouts to pull away from the  house, sometimes bringing the fascia boards with them. Preventing ice dams helps avoid damage and costly repairs.

Potential damage

Over the five-year period leading up to 2007, water damage and freezing  accounted for the second largest share of homeowner insurance claims, according  to Claire Wilkinson of the Insurance Information Institute. The average homeowner claim  for such damages was $5,531.

Ice dams are responsible for cracked plaster  ceilings and walls, peeling paint, soaked carpets, and buckled wood floors. Less  visible but no less destructive effects include drenched insulation, rotting  joists, and the formation of mold. The most common form of ice dam-related  damage is collapsed rain gutters, which can cost $100 to $300 per side to  repair.

What causes ice dams

As heat rises from a home, it melts the accumulated snow on the roof. That  melted snow travels down the roof in liquid form until it reaches the eave line  and gutter, where it refreezes due to colder temps. This ice ridge continues to  expand, blocking the flow of subsequent snow melt.

As water continues to  melt higher up the roof, it collects behind the ice dam in the form of a puddle.  Because that water sits over the warmer portion of the roof, it doesn’t  freeze.

In order for ice dams to form, there needs to be roof snow  buildup, home heat loss, and subfreezing temperatures. The more snow, the larger  the heat loss, and the longer the subfreezing temperatures remain, the higher  the likelihood that ice dams will materialize.

Preventing ice dams

Homeowners can’t control the weather, but they can do something about heat  loss. “The main goal is to keep heat from reaching the roof, thus preventing  snow melt in the first place,” explains Doug Bruell, president of Cleveland’s  25-year-old North Coast Insulation. Proper insulation and ventilation of the  attic space is intended to keep the roof surface at or near outdoor  temperatures.

Typical steps include insulating the attic floor and  installing soffit, gable and/or ridge vents to expel heat. Folding attic  stairways and recessed light fixtures also need to be insulated. “All  penetrations into the attic from the heated living space need to be addressed,” adds Bruell. Homeowners can expect to pay $800 to $1,500 to insulate the attic,  plus another $300 to $600 for the installation of vents.

The process is a  bit more involved for homes with finished attics, says Bruell. To facilitate  sufficient cold air flow from soffit vent to ridge vent, baffles or tubes are installed between the  ceiling insulation and the underside of the roof. This might involve opening up  the ceiling.

Insulation means savings

According to the U.S. Department of Energy, adding insulation to an unheated  attic will have a greater impact on energy consumption than placing it anywhere  else in the house. A properly insulated and ventilated attic not only reduces  winter heating bills, it will trim summer cooling bills by expelling heat  buildup. You can expect to save  10% to 50% on your heating and cooling bills.

In addition, you may  qualify for a federal  tax credit of up to $500.

Deicing alternatives

In theory, roof rakes, brooms, and other long-handled devices can be used to  remove snow before it has a chance to melt. In practice, however, the scheme is  difficult to pull off, considering that most homeowners can’t reach all areas of  the roof.

Electrically-heated deicing cables, which install along eave  lines to inhibit water freeze, are only moderately effective, says Bruell. “These heat cables often just back up the problem, forcing the dams to form  higher up the roof.” In addition to the purchase price ($150 to $300), and  installation ($300 to $500), these cables require electricity to run. They also  can shorten the life of roof shingles.

Ice dam removal

Homeowners suffering the effects of an ice dam—or those who fear a leak is  imminent—can hire a roofing company to remove the ice buildup. Rather than  employ hammers, chisels, and salt, which can damage the roof and gutters,  technicians will steam away the ice and remove any remaining snow. Expect to pay  around $500 or more for the service. It goes without saying that do-it-yourself  removal can be dangerous when it involves ladders, heavy ice, and slippery roofs.

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Visit HouseLogic.com for more articles like this. Reprinted from HouseLogic.com with permission of the NATIONAL ASSOCIATION OF REALTORS®.