Ice dam removal, repair and prevention in Madison

Why Madison ice-dams

An ice dam needs three things: snow on the roof, a warm roof deck above the living space, and a cold eave. Madison supplies all three. Fifty inches of snow, weeks of days that swing from 10°F to 35°F, and a housing stock full of attics that leak heat.

Heat escapes through recessed lights, the attic hatch, bath fan ducts, plumbing chases and thin insulation. It warms the roof deck, the snow melts from underneath, the meltwater runs down to the eave — which hangs out past the warm house and stays frozen — and freezes there. The dam grows, the pool behind it deepens, and water goes uphill under the shingles. The ice-and-water shield at the eaves holds it back for a while; on roofs without it, or roofs where it stops short, the water comes in over the top plate and down the inside of the wall.

The houses that ice-dam worst here are predictable. The 1900s–1930s houses on the isthmus, in Vilas, the Regent neighborhood and University Heights, with steep roofs, finished attics, knee walls and no soffit venting. The 1950s–60s ranches in Westmorland, Nakoma and Eastmorland with shallow attics and low pitches. And, more than people expect, the 1990s–2010s two-stories in Middleton Hills, Blackhawk and Sun Prairie, where a complex roof creates valleys and dead spots that the builder never vented.

Getting the ice off

For ice dam removal, Madison, WI homeowners really have two choices: steam, or something that damages the roof. Panic removal is where roofs get wrecked. Hatchets, hammers and pressure washers chip shingles, tear the membrane and shorten the roof's life by years. Rock salt eats the shingles and the gutters and kills whatever is planted below.

Low-pressure steam is the method to ask for. A steamer at about 290°F and low pressure melts a channel through the dam in minutes, the trapped water drains, and the shingles are untouched. A typical eave takes one to three hours and runs $400–$1,200 depending on the size of the dam, the height of the house and how much of the roof is involved. If water is actively coming in, the spot above the leak goes first.

No one should steam a roof at 2 a.m. or in an ice storm. Nobody should be on a roof in those conditions, and a company that offers to is one to avoid.

Repairing what the water did

Once the ice is gone and the roof dries, the damage is usually at the first three or four courses along the eave: shingles lifted and creased by ice, underlayment torn, sometimes the edge of the decking soft, and the fascia and soffit stained or rotted behind an overflowing gutter. That repair is $400–$1,500 and is typically done in spring, when a lasting fix is possible. Inside, wet insulation over the wall gets pulled and replaced, since soaked fiberglass never dries in a Wisconsin wall cavity.

If the roof is over 18 years old and the eaves have been ice-dammed for several winters, the decking along the whole eave may be gone. That's a roof replacement conversation, and one where running ice-and-water shield well up the roof is the cheapest insurance on the job.

Stopping it for good

Steam is the emergency. The fix is the attic, in this order:

1. Air-seal. Foam and caulk around every penetration through the ceiling: can lights, the attic hatch, plumbing stacks, the tops of interior walls, chimney chases. This is the single biggest step, and it's the one most often skipped because it isn't roofing.
2. Insulate to R-49 or more. That's the level commonly recommended for attics here; check the current code with your building department. Most 1960s ranches have six inches of settled fiberglass, which is about R-15.
3. Vent. Continuous soffit intake with baffles so the insulation doesn't block it, and a ridge vent or enough roof vents at the top. Good ventilation keeps the deck at outdoor temperature, so the snow doesn't melt from below.
4. Duct bath fans outside, not into the attic, where they pump warm wet air straight onto the underside of the deck.
5. Heat cable only as a last resort, on roofs where the geometry can't be fixed — a low-slope porch under a warm wall, for instance. It costs money to run every winter and it doesn't solve anything.

The roofer handles the roof; air-sealing and insulation are often a separate contractor. Focus on Energy, the state efficiency program, has offered rebates on attic air-sealing and insulation; check current offers. Our post on why ice dams form and how to stop them goes into the physics; the fall roof prep checklist covers what to do before the first snow.

What to do the day you see one

1. Look inside first. Check the ceilings and the tops of window frames along the outside walls under the dam. Photograph any water.
2. Move what can be damaged. Furniture, boxes in a closet against the outside wall, anything under a drip.
3. Clear the lower roof if you can reach it from the ground. A roof rake on the first few feet takes weight off the dam and slows its growth. Don't climb.
4. Leave the icicles alone. They're frozen to the gutter and the shingles; knocking them down tears both, and they fall hard.
5. Call for steam if water is coming in. Ask how the crew will work safely on an icy roof and whether they'll open the area above the leak first.
6. Write down the pattern. Which eaves dam, and after what weather. That record is what the attic contractor needs in spring.

Common mistakes

Chipping with a hammer or a shovel. Scattering rock salt across the roof and the beds below. Running a heat gun or a torch anywhere near the shingles. And paying for a new roof to stop ice dams when the attic is the cause: a new roof over the same leaky ceiling dams the same way, only with better membrane underneath.

Insurance

Sudden water damage from an ice dam — the stained ceiling, the ruined drywall — is often covered; check your policy. Most policies expect you to prevent further damage, so ask your insurer whether steam removal is covered, and keep the receipt. The attic work that prevents the next one generally isn't covered, and it's still the best money you'll spend on the house.