How to Get Rid of Ice Dams

Here in West Newbury winters bring plenty of snow, that Merrimack Valley effect is no joke! With that comes a familiar problem for many local homeowners: ice dams and this year has been particularly bad, for sure! These startling ridges of ice along your roof edge aren’t just unsightly. They can lead to water seeping into walls, warped floors, damaged insulation, and costly repairs if they’re not handled properly. 

What Causes Ice Dams

Ice dams form during a freeze-thaw cycle driven by uneven roof temperatures. When heat from your heated home rises into an attic that’s under-insulated or poorly ventilated, the upper portion of your roof warms and melts snow. That meltwater runs down the roof until it reaches the colder eaves and freezes again. Over time that frozen edge builds up into a dam. Behind it, water can pool and seep under shingles, dripping into interior spaces.

This same mechanism applies whether your house has a vented roof or unvented roof. In vented roofs, soffit and ridge vents allow cold outside air to move through the attic, helping keep the roof’s underside cooler and reducing the amount of snow melt. When that ventilation is inadequate or blocked, warm spots develop and fuel the formation of ice dams. In unvented roof assemblies, the attic space is part of the conditioned envelope; this can work well if insulation is continuous and air leaks are sealed, but if heat still escapes into roof bays where there’s a temperature gradient toward the eaves, you can still see dams form.

Get Rid of Ice Dams Safely

Once an ice dam has formed, tackling it incorrectly can damage shingles and gutters. Here are effective strategies from my favorite reliable source, This Old House!:

• Roof Rake from the Ground: Use a long-handled aluminum roof rake to pull snow off the roof before it melts and refreezes. Focus on the slope above the eaves where dams begin.
• Create Channels: A tried-and-true trick is to fill a tube sock or pantyhose with calcium chloride ice melter and lay it across the dam so it hangs over the gutter edge. As it works, it creates channels for trapped water to escape.
• Blow Cold Air Into the Attic: If water is actively leaking, a box fan aimed under the roof sheathing in the attic can drop surface temperatures near the dam and slow leakage while you prepare better long-term fixes.
• Avoid Hammers, Picks, or Rock Salt: Whacking at an ice dam with tools can damage roofing materials, and rock salt can harm shingles and landscaping.
• Professional Steam Removal: Roofing professionals can use steam to safely cut through ice without putting weight or stress on your roof structure.

Preventing Ice Dams Next Winter

The real key is prevention: control heat loss from your living space and manage snow before it becomes a problem.

• Insulate and Air-Seal: The biggest structural fix is to improve attic insulation and seal all air leaks so warm household air doesn’t heat the roof deck unnecessarily.
• Ventilate Properly: If you have a vented attic, ensure soffit and ridge vents are clear and balanced to maintain a cool roof deck.
• Install Heat Cables: Heated cables along roof edges and gutters gently melt snow and ice at critical points and can be a good supplement when ice dams are common.
• Keep Gutters Clean: Clear gutters in fall and after storms. Clogged gutters are more likely to back up and turn into ice barriers in winter.

For many West Newbury homeowners, understanding why ice dams happen and knowing how to address them either with DIY methods or professional help can protect homes from water damage and keep winter stress to a minimum.