Ice Dam Removal and Prevention in North Dakota

What an ice dam actually is

Heat leaks from your living space into the attic. That heat warms the roof deck and melts the underside of the snow pack. The meltwater runs down the roof until it reaches the overhang, which sits outside the heated envelope and is therefore cold. There it refreezes into a ridge of ice. Every subsequent bit of meltwater backs up behind that ridge, and standing water finds its way under the shingle course and into the house.

This matters: the ice dam is a symptom. The cause is heat in your attic. You can remove the ice every January for twenty years and never fix anything.

Stopping the water today

What works

• Steam. Low pressure steam melts a channel through the dam and lets the trapped water drain. It is the only method that does not damage the roof. This is what a professional crew uses.
• Calcium chloride in a sock. Fill a nylon stocking with calcium chloride ice melt, lay it vertically across the dam so it melts a drainage channel. Slow, but it is safe and you can do it yourself from a ladder.
• Clearing the lower three or four feet of snow with a roof rake from the ground. Removes the fuel before it melts. Do this after every heavy snowfall and most dams never form.

What damages your roof

• Chipping with a hammer, axe or chisel. Cold shingles are brittle. You will crack the mat and turn a water problem into a replacement.
• Pressure washing. Drives water under the shingles, which is the exact thing you are trying to stop.
• Rock salt. Sodium chloride corrodes metal flashing, gutters and fasteners, and kills the landscaping it drips onto. Calcium chloride is the correct product.
• Going up on an iced roof. Not worth it. People die doing this every winter.

The permanent fix, in priority order

1. Air sealing the attic floor

This is the highest-return item and the one that gets skipped. Warm air rises through every penetration in your ceiling: recessed lights, bath fans, plumbing stacks, the attic hatch, top plates, wiring holes. Sealing those with foam and caulk stops the heat before it reaches the deck. Insulation alone does not do this, because air leaks straight through insulation.

2. Insulation depth

North Dakota attics should be at R-49 to R-60. Many older Minot homes are at R-19 to R-30. Adding depth after air sealing keeps the remaining heat where you paid for it.

3. Balanced ventilation

The roof deck needs to stay at outdoor temperature. That takes intake at the soffit and exhaust at the ridge, roughly balanced. The failure we find constantly: a good ridge vent with soffit intake blocked by blown-in insulation. Baffles at each rafter bay fix it, and it is cheap work.

4. Heat cable, last

Heat cable in a zigzag at the eave keeps a drainage channel open. It is a legitimate tool on a problem eave that cannot be fixed structurally, such as a cathedral ceiling with no attic to seal. It is not a fix, it is a bypass, and it costs money to run all winter.

If water already got in

1. Photograph everything before you clean up, for your insurer.
2. Get the ice channel opened so water stops accumulating.
3. Pull wet insulation. Wet insulation has no R-value and will grow mold.
4. Call your insurer. Sudden water damage from an ice dam is usually covered. Long-term seepage from a known problem usually is not, which is another reason to act fast.

Why some houses get them and the neighbor does not

Same street, same weather, one roof has a foot of ice and the other is clear. The difference is almost always attic air sealing and intake ventilation. Occasionally it is a complex roof geometry that traps snow in a valley, or a low-slope eave over an unheated porch. It is essentially never the shingle brand.

Questions we get asked