Ice dam removal: how to clear ice dams safely, handle leaks inside and stop them for good

How ice dams form

Three things have to come together, says the US Department of Energy's Building America Solution Center: snow on the roof, an attic that is poorly air sealed or poorly insulated, and freezing weather outside. As little as 2 inches of snow is enough.

1. 01

   Warm air leaks into the attic

   Heat rises from the rooms below through gaps around lights, pipes, wiring, flues and the attic hatch.

2. 02

   The roof deck warms

   Snow resting on the warm part of the roof melts from underneath, even on a freezing day.

3. 03

   Meltwater runs to the eaves

   The overhang has no heated room beneath it, so it stays as cold as the outdoor air.

4. 04

   The water refreezes

   A ridge of ice builds along the edge, and every melt-freeze cycle makes it bigger.

5. 05

   Water ponds and backs up

   Meltwater pools behind the ridge, works up under the shingles and leaks into the attic, the walls and the ceilings near the outside walls.

A handout from Michigan building inspectors notes that ice dams typically build when outdoor temperatures sit in the low 20s °F for several days with several inches of snow on the roof, and that keeping the attic air below freezing in that weather reduces them.

Signs you have an ice dam

• A thick ridge of ice along the eaves or filling the gutters, often with heavy icicles.
• Bare or thin patches of snow higher up the roof while the rest is still covered: heat is escaping there.
• Water stains or drips on ceilings and walls near the outside walls, especially after a thaw.
• Wet or matted insulation, frost or damp wood in the attic.

ENERGY STAR lists a history of ice dams among the signs of serious air leaks from the house into the attic.

Ice dam removal from the ground

Roof rake tips

• Choose a rake with a long enough handle to reach from the ground, and a non-conductive handle if there are overhead lines anywhere nearby.
• Work from the side of the falling snow, never directly under the eaves.
• Clear the gutters and downspouts of snow and ice where you can reach them from the ground so meltwater can drain.
• Rake after each heavy snowfall rather than waiting for a deep, heavy layer.

What damages roofs during ice dam removal

• Chipping or hammering at the ice. Michigan building inspectors warn it will likely damage shingles. Scraping the shingles with a shovel or ice chopper does the same.
• Routine salt or calcium chloride. Both are corrosive to metal gutters, downspouts and flashing, and runoff can damage grass and plants below.
• Climbing onto the roof. Ice, snow and frozen ladder footing are a fall waiting to happen. Winter roof work is for professionals with fall protection.
• Ignoring the attic. Clearing the ice treats the symptom; the warm attic will build a new dam with the next snow.

Ice dam leaking into the house: what to do

1. 01

   Protect what is below

   Move furniture and electronics, lay towels and put buckets under drips.

2. 02

   Stay safe around electricity

   If water is near light fixtures, outlets or switches, switch off that circuit at the breaker, but only from a dry spot. Our ceiling leak guide covers bulging ceilings and wet wiring.

3. 03

   Look in the attic

   Check for wet insulation and dripping sheathing near the eaves. ENERGY STAR lists wet insulation among the conditions that call for a professional.

4. 04

   Relieve the dam from outside

   Rake the snow and, if water keeps coming, open a drainage channel as described above.

5. 05

   Record the damage

   Photograph stains, wet insulation and the ice outside for your insurer.

6. 06

   Dry quickly

   Fans and a dehumidifier help; wet drywall, insulation or carpet that stays damp invites mold. See water damage restoration for larger leaks.

How to prevent ice dams: air sealing, insulation and ventilation

The lasting fix is a cold roof. Building America lays out three steps, in order, and calls air sealing the most important.

1. Air seal the ceiling

ENERGY STAR recommends air sealing the attic before adding insulation, and notes that air sealing combined with insulation helps prevent ice dams. Common leaks to seal:

• Recessed lights, wiring holes and plumbing pipes and vent stacks.
• The attic hatch or pull-down stairs.
• Kneewalls and dropped soffits open to the attic.
• Furnace flue and duct chases, and the gap around chimneys.
• Exhaust fan housings, top plates and ceiling drywall seams.

Around flues and chimneys, ENERGY STAR notes that codes generally require 1 inch of clearance from metal flues and 2 inches from masonry chimneys to combustible material, so those gaps are closed with aluminum flashing or sheet metal and high-temperature silicone caulk, not foam. Bathroom, kitchen and dryer vents must discharge outdoors, never into the attic.

2. Insulate the attic

Once the air leaks are sealed, add insulation to slow heat loss into the attic. Our attic insulation guide covers how much you need by climate zone, and our guides to blown-in insulation and spray foam insulation compare the materials.

3. Keep the attic ventilated

ENERGY STAR explains that a well-vented attic stays cold in winter. Never cover soffit vents with insulation; fit rafter vents (insulation baffles) between the rafters at the eaves so outside air can flow in, and Building America calls for an air gap of at least 2 inches between the top of the insulation and the underside of the roof deck.

Safety before you seal

• Combustion appliances: sealing can make naturally vented gas or oil appliances backdraft. ENERGY STAR advises having them tested by a home performance contractor before and after sealing, and a working carbon monoxide detector is a sensible companion.
• Vermiculite: pebble-like attic insulation may contain asbestos; leave it undisturbed until it has been tested. See asbestos testing.
• Knob-and-tube wiring: common before about 1930, it can be a fire hazard in contact with insulation. Call an electrician first.

When you reroof

Building America notes that codes often require a self-adhered waterproof membrane on the roof deck along the eaves as an extra layer against ice dam leaks. If your roof is due for replacement, ask the roofer how far up the roof the membrane will run. Clean gutters help meltwater drain during a thaw, though on their own they do not prevent ice dams: see gutter cleaning.

Roofer, insulation contractor or both

• Ice on the roof now: a roofer or ice dam removal service with fall protection.
• Leak damage inside: see roof leak for repairs to shingles and flashing once the ice is gone.
• Ice dams every winter: a home performance contractor or energy auditor to find the air leaks, then an insulation contractor. Ask them which leaks they found, how they will seal around flues, whether they will test combustion appliances, and how they will keep the soffit vents clear.

Sources

Official and building science guidance, checked on 27 October 2026.

• US DOE Building America Solution Center · Attic air sealing, insulating and ventilating for ice dam prevention ↗Three conditions, 2 inches of snow, the order of fixes, common air leaks, 2-inch ventilation gap, eave membranes.
• ENERGY STAR · Attic air sealing project ↗Air sealing against ice dams, leak locations, flue clearances and materials, backdrafting, vermiculite, knob-and-tube wiring, when to hire a professional.
• ENERGY STAR · About attic ventilation ↗Cold attic in winter, soffit vents, rafter vents.
• City of Bothell, Washington · Preventing roof collapse and damage from ice ↗Roof rake limits, tap water channels from the lower edge, channels lasting days, signs of an overloaded roof, based on University of Minnesota Extension guidance.
• Muskegon Charter Township building inspectors · Ice dams ↗Low 20s °F conditions, keeping the attic below freezing, no chipping, salt and calcium chloride corrosion, venting fans outdoors.
• CDC NIOSH · Ladder safety ↗Ladder deaths, 75-degree angle, 3 feet above the roof edge, three points of contact, 10 feet from power lines.