You notice the icicles first. Then a brown stain shows up on the ceiling near an outside wall, or water starts dripping from the top of a window frame in the middle of February. In Maine, that's almost always an ice dam, and the water it pushes into the house can soak attic insulation, ceilings, and the walls below before anyone sees a drop.
This guide explains what causes ice dams, what to do when the ceiling starts leaking, and how to stop them from coming back. If the water has already gotten in, Mattra provides water damage restoration for Maine homes, and we also do the insulation and air sealing that prevent the next ice dam.
What an Ice Dam Is
An ice dam is a ridge of ice that forms along the bottom edge of a roof. Here's how it happens:
- Heat escapes from the living space into the attic and warms the underside of the roof.
- Snow on the warm part of the roof melts and runs downhill.
- When the meltwater reaches the eaves, which hang out past the warm walls and stay cold, it refreezes.
- The ice builds into a dam, and the next meltwater pools behind it.
Shingles shed water running downhill. Water pooled behind an ice dam backs up under them instead and finds its way through the roof deck into the attic, the top of the walls, and the ceiling.
Signs You Have an Ice Dam
- Thick icicles hanging from the gutters, or ice built up on the soffits
- Stains, peeling paint, or bubbling on ceilings near exterior walls
- Water dripping from the top of window and door frames
- Damp or matted insulation in the attic, or frost on nail tips and the underside of the roof deck
- A roof where the snow has melted near the peak but piled up in a ridge of ice at the edge
Big icicles on their own aren't proof of a leak, but they tell you the conditions for an ice dam are there.
The Ceiling Is Leaking: What to Do Now
- Catch the water. Buckets and towels under every drip, and furniture moved out of the way.
- Turn off power to any light or ceiling fan in the wet area at the breaker. Water and fixtures don't mix.
- Watch for a sagging ceiling. A bulge means water is pooling above the drywall or plaster. Keep people out from under it and call for help.
- Take the snow load off safely. A roof rake used from the ground can pull snow off the lower few feet of the roof so less meltwater feeds the dam. Stay off an icy roof.
- Leave the ice alone. Chopping at an ice dam with a hammer, axe, or shovel breaks shingles and makes the leak worse.
- Photograph the damage and call your insurance company.
What Ice Dam Water Does Inside the House
An ice dam leak tends to be slow and spread out, which makes it easy to underestimate. Water runs down the roof deck, soaks into attic insulation, collects on top of the ceiling, and works its way into the top of the exterior walls. By the time a stain shows, the insulation above it has usually been wet for a while.
- Wet insulation compresses and stops insulating, which makes the heat loss worse and feeds the next ice dam. Soaked cellulose and fiberglass usually has to come out. That's a job for insulation removal.
- Ceilings stain, sag, and can come down if enough water pools above them.
- Roof sheathing and framing that stay damp start to grow mold and eventually rot. See rot repair.
- Attic mold often follows a winter of leaks. If you see dark staining on the underside of the roof deck, read about mold removal and remediation.
The fix starts with drying. A wet ceiling and attic need the soaked insulation removed, airflow and dehumidification in the cavity, and moisture readings before anything is patched and painted. Our guide to how long water damage takes to dry covers what that process looks like.
How to Stop Ice Dams for Good
Heat cables, roof rakes, and calcium chloride can buy time, but they treat the ice. The ice forms because heat is getting into the attic. Fix the heat loss and the dams stop forming.
- Air seal the attic floor. Warm air leaks into the attic through gaps around light fixtures, bath fans, plumbing and wiring holes, the chimney, top plates, and the attic hatch. Air sealing closes those paths, and it's the single biggest step.
- Add attic insulation. Once the air leaks are sealed, enough attic insulation keeps the heat in the house and the roof deck cold.
- Ventilate the attic. Soffit and ridge vents keep the underside of the roof close to outdoor temperature. See attic ventilation.
- Repair the roof if the leak damaged it. Lifted shingles and failed flashing let water in more easily next time. See roofing.
Air sealing and attic insulation often qualify for Efficiency Maine rebates, and they lower the heating bill every winter after.
Does Insurance Cover Ice Dam Damage?
Many homeowners policies cover the water damage inside the house from an ice dam, like the wet ceiling, walls, and insulation. Fixing the roof itself, removing the ice, or correcting the heat loss is often treated as maintenance. Policies vary, so call your agent early. Mattra works with your insurance company on water damage claims.
Common Questions About Ice Dams
Do ice dams mean I need a new roof?
Usually no. Most ice dams come from heat escaping into the attic. A roofer can fix damaged shingles, but the dams keep coming back until the attic is air sealed, insulated, and ventilated.
Are heat cables worth it?
Heat cables can melt a channel through the ice in a known trouble spot, but they use electricity all winter and only protect the strip of roof they cover. Air sealing and attic insulation remove the cause.
Should I knock the icicles down?
Small icicles you can reach safely from the ground can come down. Don't climb onto an icy roof or chop at the ice dam itself, since that breaks shingles and causes leaks.
Ice Dam Water Damage Help in Central Maine
Mattra has worked on Maine homes since 1996, and ice dams are a big part of every winter for us. We dry out the ceilings, walls, and attics they soak, replace the insulation, rebuild what's damaged, and seal the attic so it doesn't happen again. One team handles both the water damage and the cause.
Cold snaps cause trouble inside the walls too. Read what to do when a frozen pipe bursts.