Ice Dams

What Is an Ice Dam?

A ridge of ice that forms at the edge of a roof that prevents melting snow from draining. Water backs up behind the dam and can leak into the home. In Colorado, our sunshine can make temperatures get high and then quickly cool by 30° or more once shade hits, which then gets the dams re-forming.

How Do I Find Signs of Ice Damming?

Look closely at icicles forming on your home. If they are coming out of gutters, but there is no water trapped behind them, then the likelihood is small of a dam forming. But, this can be a sign of dams to come.

Check for stains, moisture, or icicles inside the attic, or along ceiling of outside walls, and soffits or soffit vents (the underside of the eaves, which is the overhang of roof). This may reflect a dam forming or having formed.

How Can I Fix This?

Have a roofer inspect all roof sections, removing ice and snow in any formed dams. They will be able to advise, if damage has happened, on repairs. If your home’s orientation to sunlight is not letting the dam areas get sun, you can put a stocking filled with ice melt product (i.e. calcium chloride) vertically across the ice dam, and it will melt a channel for defrosting. This is purely a temporary fix, do not count on this to save your roof with time, and salt can do damage as well.


The best prevention is keeping the roof the same temperature at the eaves. This is done by increasing ventilation on the eaves, adding insulation, and sealing every possible air leak that may warm the underside of the roof. A roofing professional can help with venting, as just a bunch of extra venting does not warrant better ventilation, it is placement and style that is necessary to efficiently keep temperatures and dryness at a constant, etc.

*Some date gather from Nov/Dec 2017 Common Ground publication.

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