What is an ice dam?

An ice dam is a thick ridge of ice that forms along the cold edge of your roof. Warm air inside your home melts snow higher up on the roof. The water runs down, refreezes at the eaves, and builds a barrier. Water can then back up under shingles and leak into the house.

Signs you may have a problem

• Large icicles hanging from gutters
• A thick band of ice at the roof edge
• Water stains on ceilings or exterior walls after a thaw
• Peeling paint or damp insulation in the attic
• Drafty rooms or a musty smell near exterior walls

Quick prevention you can do today

• Rake the roof after snowfalls. From the ground, use a roof rake to clear the lower 3 to 4 feet of snow.
• Keep gutters clear. Clean leaves in fall and check downspouts so meltwater can flow.
• Open attic vents. Make sure soffit and ridge vents are not blocked to keep the roof deck colder.
• Seal warm air leaks. Foam or caulk gaps around lights, hatches, plumbing stacks, and wires.

Safe short-term fixes if ice forms

• Create melt channels. Fill long socks with calcium chloride ice melt and lay them across the ice so one end hangs over the gutter. Do not use rock salt.
• Rake again. Remove loose snow above the dam to reduce meltwater feed.
• Manage leaks inside. Place a bucket under drips. Pop a small hole in a bubbled ceiling to relieve pressure and direct water into the bucket.

Do not: chip ice with tools, spray hot water, or use open flames or heat guns.

Long-term fixes that solve the cause

1. Air seal the attic. Seal gaps around can lights, fans, plumbing, and the attic hatch.
2. Add insulation. Aim for your local recommended R-value. Many cold zones target R-49 to R-60.
3. Improve ventilation. Clear soffit vents and add baffles so insulation does not block airflow.
4. Vent exhausts outdoors. Bathroom and kitchen fans should not dump air into the attic.
5. Consider heat cables. Self-regulating cables can help in problem areas when installed by a pro.
6. Upgrade during re-roof. Ask for ice and water shield along eaves and valleys.

When to call a roofer or insulation pro

• Active leaks, sagging drywall, or stained ceilings
• A thick dam that grows after each storm
• Steep roofs or limited access
• Projects like air sealing, added insulation, or ventilation changes
• Installing heat cables or upgrading underlayment

Simple checklist for the next snow

• Rake the lower 3 to 4 feet of roof snow
• Keep gutters and downspouts open
• Watch for new icicles and ceiling stains
• Place calcium chloride socks if water is backing up
• Schedule an attic air seal and insulation review

FAQs

Do gutters cause ice dams?
Gutters do not cause ice dams by themselves. They can make icicles look worse. The root cause is warm air escaping into the attic and melting roof snow.

Are heat cables a cure by themselves?
Heat cables help in tough spots, but air sealing and insulation are the main fix. Many homes use both.

Should I clear the whole roof?
No. Removing the lower few feet is usually enough. Never climb on an icy roof.