Ice Dams in Cincinnati: Roof, Gutter, and Home Damage

An ice dam is a ridge of ice at the edge of the roof that traps melting snow behind it. The trapped water backs up under the shingles and can leak into ceilings, walls, and insulation. The usual cause is heat escaping into the attic, and the usual fix is air sealing and insulation.

The Cincinnati airport averages about 23 inches of snow a year, based on NOAA's 1991-2020 normals. The snow itself is not the main problem. The damage comes when that snow melts, refreezes, and melts again.

How ice dams form

It starts with heat leaking from the house into the attic. That heat warms the roof deck, and snow on the upper roof melts. The water runs down toward the eaves. The eaves hang past the heated part of the house, so they stay cold. The water freezes there and forms a ridge of ice.

As the cycle repeats, the ridge grows into a dam. Meltwater pools behind it with nowhere to go. It works under the shingles, soaks the roof deck, and gets into the house.

Our winters make this worse. The same NOAA normals count about 100 nights a year at or below freezing at the airport, but only about 22 days that stay below freezing all day. That means many winter days thaw and then refreeze at night.

The damage ice dams cause

Roof damage. Water backing up under shingles wears out the underlayment and soaks the roof deck. Over several winters, the plywood can rot where you cannot see it from outside. By the time you find a soft spot or a ceiling stain, the damage is bigger. If you see these signs, have a roofing inspection done.

Gutter damage. Ice is heavy. A gutter packed with ice can weigh several pounds per foot, so a 30-foot run can pull more than 100 pounds on the fascia. Hangers bend, gutters sag, and fascia boards rot from the constant moisture. Our gutter guide covers what to look for, and our gutter repair page explains how we can help.

Interior water damage. Once water gets past the roof deck, it follows the rafters. It can show up as ceiling stains, peeling paint, or damp spots far from where it got in. Moisture that stays can lead to mold in attic insulation and wall cavities. If water has already gotten in, see our water damage guide and our water damage restoration page.

Siding and exterior damage. Meltwater spilling from clogged gutters runs down the siding, freezes, and can work its way behind panels. Over time this can rot the wood behind vinyl siding and wear at fiber cement joints. Learn more about how temperature swings affect siding.

Prevention starts in the attic

Most ice dams start with heat escaping into the attic. Fixing that lowers the chance of ice dams. The National Weather Service notes there is no way to guarantee an ice dam won't form, but these steps help.

Air sealing. Warm air leaks into the attic through gaps around light fixtures, plumbing stacks, attic hatches, and ductwork. University of Minnesota Extension says air leakage is, in many homes, the major way heat reaches the roof and leads to ice dams. Its advice is to seal the ceiling first, then add insulation.

Insulation. ENERGY STAR recommends attic insulation of R-49 to R-60 for climate zone 4A, which includes the Cincinnati area. Many older homes have far less. More insulation keeps heat in the living space and off the roof deck.

Ventilation. A well-vented attic stays closer to the outside temperature, so snow melts more evenly. Soffit vents at the eaves and ridge vents at the peak keep air moving. Make sure insulation is not blocking the soffit vents, a common problem in older homes.

What to do if you already have ice dams

Do not chip at ice dams with a hammer, chisel, or ice pick. You can crack shingles and damage the gutters.

Calcium chloride. Travelers Insurance suggests filling a nylon stocking with calcium chloride ice melt and laying it across the ice dam to melt a channel. Do not use rock salt (sodium chloride), which Travelers says can damage your roof.

Roof rake. From the ground, a roof rake can pull the first three to four feet of snow off the roof edge. That leaves less snow to melt and refreeze. UMN Extension warns that rakes can damage roofing, so pull gently and do not scrape down to the shingles.

Get help for big dams. Do not climb onto an icy roof. If you cannot reach the ice safely from the ground, hire a professional.

Is ice dam damage covered by insurance?

Often, the damage is. Removing the ice usually is not. Progressive explains that dwelling coverage may pay to repair ice dam damage to your roof, walls, and other parts of the house. It also says insurance typically won't pay to remove the ice dam, and damage that happens gradually from poor maintenance is typically not covered. Your own policy decides, so read it and ask your agent.

Keep records of any insulation, air sealing, or ventilation work. Take photos of the damage before cleanup. Our Ohio insurance claims guide explains how to file and what your insurer must do.

Inspect your roof and gutters every spring

The best time to check for ice dam damage is after the last hard freeze. In our area, that is usually mid- to late April. The National Weather Service lists the average last 32°F date as April 16 at Lunken Airport, April 18 at the Cincinnati airport, and April 22 at Hamilton (NWS Wilmington spring frost and freeze data). You do not have to wait for that date to look from the ground, though.

Look for sagging gutters, stained fascia, ceiling spots, and flattened attic insulation. These are signs that ice dams did their work over the winter.

A spring exterior check catches these problems while they are still small repairs.

If you see signs of ice dam damage or want to prevent problems before next winter, schedule a free inspection with our team.