Ice Dams Forming on Roof Edge
Address within 1–2 weeks to prevent further damage
Ice dams causing leaks? Learn safe removal methods, prevention costs ($500–$3,000), and the attic ventilation fix that stops them permanently. Estimated repair cost: $500–$3,000. For a precise estimate based on your actual roof, get a free satellite quote at RoofVista.
Likely Causes
Warm attic air melts snow on the upper roof, which refreezes at the cold eave creating a dam
Inadequate attic insulation lets heat escape through the roof deck
Poor attic ventilation prevents cold air from flushing warm air out before it melts snow
Complex roof geometry with valleys and dormers creates natural collection points for ice
Heat sources in the attic (ducts, recessed lights) create warm spots that accelerate melting
How to Diagnose This Problem
- 1
Look for icicles hanging from the eave — large icicles indicate ice dam formation behind them
- 2
Check attic temperature in winter — it should be within 10°F of outdoor temperature; warmer means heat loss
- 3
Look for water stains on interior walls or ceilings near exterior walls (ice dam leak evidence)
- 4
Check attic insulation depth — code requires R-49 (about 16" of fiberglass) in cold climates
- 5
Verify soffit vents are not blocked by insulation — this is the #1 cause of poor attic ventilation
Estimated Repair Cost
$500 – $3,000
Typical repair range (varies by location and severity)
When to Replace Instead of Repair
If ice dams have caused repeated leaks over multiple winters, the underlying insulation and ventilation problems should be fixed during a roof replacement. Adding ice-and-water shield in the first 6 feet from the eave prevents future ice dam leaks.
Materials Affected
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