Minnesotans warned as ice dam season approaches

The Minnesota Department of Commerce is expecting ice dams to be back in force. In preparation, the department urges Minnesotans to take action now to prevent ice dams and halt what can become a costly home repair issue.

CAUSE OF ICE DAMS

Although sometimes thought of as a problem with roofing or attic ventilation, ice dams are actually caused by the presence of warm, moist 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 snowmelt and ice pile up. The ice buildup can back up under the shingles, damaging them and allowing water to leak to the ceilings and walls below.

SOLVING ICE DAMS

Attic air leaks around wires, plumbing vents, light fixtures and chimneys must be sealed with caulking or expanding spray foam, and attic insulation should be installed to a minimum R-50 as space allows.

A first step in solving ice dams, and to making your home more energy efficient, is to have an advanced energy audit. The audit will use equipment such as infrared cameras to identify air leaks and will offer action steps to prevent ice dams. Advanced energy audits can be facilitated by your gas or electric utility.

WHAT NOT TO DO

• Installing heating cables will shorten the roof life and cost money to operate.

• Removing ice with shovels, chippers, chemicals or heat can damage shingles, gutters, and other building components.

• Adding roof vents, including powered vents, will not eliminate ice dams and often makes the problem worse.

• Inadequate insulation, especially near the eaves, is a contributing cause of ice dams. Adding insulation, especially on the top plate of exterior walls, can reduce heat transfer to the roof deck, but insulation alone is insufficient to stop air leaks or prevent ice dams.

For more information on ice dams and ways to conserve energy in your home, check out the Department’s energy guide “Home Envelope” or visit www.energy.mn.gov.

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