Roof problems
Ice dams: why they form and how a new roof helps
Ice dams form when heat from the house melts snow on the upper roof and the water refreezes at the colder eaves, building a ridge of ice that backs water up under the shingles. The lasting fixes are keeping the attic cold, with better insulation and ventilation, and protecting the roof edge with ice and water shield when the roof is replaced.
Updated September 14, 2026
How an ice dam causes a leak
Shingles shed water that flows downhill. Water trapped behind a ridge of ice sits still and works its way up and under the shingles, then through the deck into walls and ceilings.
Signs you have ice dams
- Thick ice along the gutters and eaves
- Large icicles, especially over windows
- Water stains near the tops of exterior walls after a thaw
- Snow melting on the upper roof while the eaves stay frozen
What a roof replacement changes
- Ice and water shield at the eaves, required by code, which seals around nails and keeps backed-up water out
- Full ice and water coverage on our Core and Complete options
- A ridge vent that lets warm, moist air out of the attic
- A chance to check soffit vents and insulation while the deck is open
What to do now
- Don’t chip ice off the roof, because it damages shingles
- Pull snow off the lower few feet of the roof from the ground with a roof rake
- Watch for ceiling stains and photograph them
Questions
- Will a new roof stop ice dams completely?
- A new roof with ice and water shield stops ice dams from causing leaks at the edge. Preventing the ice itself depends on keeping the attic cold, which comes down to insulation and ventilation.
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