Ice Dams: What Causes Them and How to Prevent Them
October 5, 2026 · 4 min read
Ice dams are ridges of ice that build up along the eaves in winter and push meltwater back under the shingles. They are one of the most common causes of winter roof leaks in New England, and they are usually a symptom of what is happening in the attic.
What causes an ice dam
Heat from the living space escapes into the attic and warms the roof deck. Snow on the warm part of the roof melts, runs down to the cold eave, and refreezes. Over days the ice builds up and traps meltwater behind it, which can seep under shingles and into the house.
Signs you have one
- Thick ice along the lower edge of the roof, often with large icicles
- Water stains on ceilings or walls near exterior walls
- Peeling paint or damp insulation near the eaves
- Gutters pulled away or bent under ice
Safe short-term steps
These reduce damage while you arrange a lasting fix.
- Clear snow from the lower few feet of the roof with a long-handled roof rake, working from the ground
- Never chip or pick at the ice with tools; it damages shingles and can hurt you
- If water is entering the house, move belongings, protect floors, and call a professional
Lasting fixes
The permanent solution is keeping the roof deck cold and even: seal air leaks from the living space into the attic, add insulation to a suitable level, and make sure the attic is properly ventilated. Roof work such as replacing damaged shingles or flashing helps, but it does not remove the cause on its own.
When to call for help
If ice dams return every winter, or you see interior water stains, have the roof and attic looked at before the next cold season. Fall is the best time to deal with it.
Need a hand? See our roofing services or request a free estimate.
More guides
Ready to get started?
Tell us about the job and we will get back to you with a straight answer on price and timing. Estimates are free.