How to stop
ice dams
Why New England roofs get ice dams — and the three-part fix that actually prevents them.
By Eric Murray, owner · MA CSL #077319 · HIC #174394Updated May 30, 2026
Preventing ice dams in New England
If you’ve seen thick ice ridges along your eaves and icicles hanging from the gutters, you’ve seen an ice dam. They’re a New England rite of winter — and a real threat to your roof and walls. The good news: they’re preventable.
Why they form
Warm air leaking into the attic heats the roof deck and melts the snow above it. That meltwater runs down to the cold eaves and refreezes, building a dam. Water then pools behind the dam and works its way under the shingles and into the home.
The three-part fix
1. Air-seal & insulate. Stopping heat from reaching the roof deck keeps it cold and snow from melting unevenly. 2. Ventilate. Balanced soffit-to-ridge airflow keeps the deck temperature consistent. 3. Ice-and-water shield. A waterproof membrane at the eaves and valleys protects the vulnerable areas if a dam does form.
Don’t just chip the ice
Hacking at ice or relying only on roof rakes treats the symptom. Addressing insulation and ventilation treats the cause — and that’s what we build in when we re-roof or insulate.
Frequently asked
What causes ice dams?+
Heat escaping into the attic melts snow on the upper roof; the water refreezes at the cold eaves, forming a dam that backs water up under the shingles. It’s an insulation and ventilation problem as much as a roofing one.
How do I prevent ice dams for good?+
A combination of air-sealing and insulation (to keep the roof deck cold), proper soffit-to-ridge ventilation, and ice-and-water shield at the eaves. We address all three.
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