Ice dam forming on roof edge

Symptoms

• Thick ridge of ice along the roof edge or gutters
• Icicles hanging heavily from the eave
• Water stains appearing on ceilings near exterior walls in winter

Likely causes

• CommonHeat loss into the attic melting snow unevenlyWarm roof deck melts snow above the living space while the eave stays cold, so meltwater refreezes there.
• CommonPoor attic insulation or air sealingGaps around lights, hatches, or ducts let heat leak into the attic.
• PossibleClogged gutters holding meltwaterIce and debris in gutters gives meltwater nowhere to go but back under the roof.

What to do

1. Use a roof rake from the ground to remove snow within a few feet of the eave to reduce meltwater feeding the dam.
2. Never chip or hack at the ice with an axe or hammer, which can damage shingles.
3. Fill a nylon stocking or leg of pantyhose with calcium chloride ice melt and lay it across the dam perpendicular to the eave to create a channel for water to escape; avoid rock salt on roofing.
4. Check the attic for warm spots, gaps around light fixtures, or missing insulation once safe to do so.
5. Improve attic insulation and air sealing before next winter to prevent recurrence.
6. Make sure gutters are clear before the first snow of the season.
7. If water is actively entering the house, contain it and call a roofer or ice-dam removal service.

Tools and parts

• Roof rake
• Nylon stocking
• Ladder (for ground-level tasks only)

When to call a pro

Call a professional ice-dam removal service (steam-based) for large dams, and an insulation contractor to fix the root cause.

Safety