Every February and March at Sundown Exteriors, the phone lights up. Ceiling stains showing up on second-floor bedrooms. Water dripping out of recessed lights. Wet insulation in the attic. The first guess is usually “the roof must be leaking.” It is, but the actual culprit is almost always an ice dam.
Illinois winters are practically designed for ice dam formation. Cold enough to keep eaves below freezing, warm enough that snow on the roof partly melts, plus a lot of older housing stock with attic insulation that’s not doing its job. Every variable lines up to make them an almost annual event in Bloomington-Normal and Peoria.
Already seeing icicles or ceiling stains? Call us at (309) 275-6801 or book a free inspection online. We do steam-based dam removal that won’t damage the shingles, and we’ll tell you what’s driving the problem in the first place.
How an Ice Dam Actually Forms
It’s a three-ingredient recipe: snow on the roof, heat escaping into the attic from the house below (warming the upper portion of the roof deck above 32°F), and eave temperatures still below 32°F (because the eaves overhang the warm house). Snow on the warm upper roof melts. Water runs down. Hits the cold eave, refreezes. The dam grows taller. Eventually the dam is high enough that meltwater pools behind it and works its way through shingle seams into the deck, the insulation, and your ceiling. The icicle hanging off the gutter is just the visible symptom.
Why Illinois Is Especially Brutal for Ice Dams
This isn’t the coldest state in the country, Minnesota and the Dakotas see colder winters. But cold isn’t actually the issue. The issue is temperatures that bounce around 32°F.
Illinois winters hit that pattern hard from January through March: daytime highs in the 40s, overnight lows in the 20s, with snow on the roof melting and refreezing daily. Combined with 22 to 28 inches of seasonal snow and a lot of pre-1970 housing stock with substandard attic insulation and ventilation, it’s a perfect storm. And once the sun starts hitting south-facing slopes in late winter, even sub-freezing air doesn’t stop the melting.
What the Damage Actually Costs
The icicle hanging off your gutter is the symbol. The bill is usually some combination of:
- Wet attic insulation ($2,000 to $5,000 to replace once it loses R-value)
- Deck rot when the OSB or plywood absorbs water (see decking damage)
- Drywall and paint damage ($700 to $3,500 in interior repairs)
- Mold growth once the warmer months arrive
- Shingle and flashing damage as water works backward under shingles (see when water stains start showing up)
- Gutter damage ($1,500 to $4,000 to replace gutters bent under ice load)
A single bad ice dam event on a Bloomington-Normal home commonly runs $4,000 to $12,000 once everything’s added up.
That’s why this is worth taking seriously.
If You Have One Right Now
If you see a dam forming and the forecast is calling for more cold, here’s what to do (and not do): Don’t chop at it with an axe or hammer. Most common Illinois DIY mistake we see. You’ll damage the shingles underneath, often badly.
Calcium chloride in pantyhose works. Lay the bag perpendicular to the dam to melt a vertical channel for drainage. Avoid rock salt, it eats metal flashing and gutters.
Rake snow off the lower 3 to 4 feet of the roof. A roof rake (the long aluminum pole with the wide blade) from the ground works. Don’t climb on a snowy roof.
For active leaks, call a professional. Specialized steam equipment melts the dam without harming the shingles.
That’s what most reputable Illinois roofers use. See how to remove ice dams safely.
Document interior damage. Photos for insurance, dated.
Ice dams are usually classified as maintenance, but sudden interior damage from a specific event sometimes qualifies for coverage.
The Permanent Fix
The honest truth: removing a dam is a temporary fix.
If your insulation and ventilation are the same next December, the dam comes back. The permanent solution has three legs: 1. Better attic insulation. Get to R-49 or higher.
Most older Illinois homes have less. Air sealing (around recessed lights, attic hatches, plumbing penetrations) matters as much as the R-value itself. See how insulation affects roof lifespan.
2. Proper attic ventilation. Continuous ridge venting plus adequate soffit intake keeps the deck cold. Cold deck doesn’t melt the snow above it. Ventilation matters specifically in Illinois.
3. Ice and water shield at the eaves. Self-adhered membrane under the shingles at the eaves and in valleys gives you a waterproof backup even when a dam forms. Modern Illinois code requires it, but older roofs often have only the bare-minimum 2-foot coverage. A quality install goes 6 feet up. More on that. For the broader prevention checklist, see how to prevent ice dams in Illinois.
If you’re already planning a reroof, this is the moment to address all three. The cost premium is modest when you’re doing the work anyway. The cost to retrofit later is a lot higher.
Quick Answers
Does insurance cover ice dams? Most Illinois policies cover the resulting interior water damage but not the dam removal or the underlying ventilation/insulation problem. Check your policy.
Will heat cables solve it? Only as a supplement. They melt a channel through the dam but don’t address the heat loss that caused it. Use them on chronic problem areas, not as the main fix.
Can I just remove the snow? Yes, with a roof rake from the ground. Don’t climb a snowy roof. It’s a temporary fix though, the underlying conditions still exist.
Will a new roof solve it? Only if the reroof includes ventilation upgrades, extended ice and water shield, and an honest look at attic insulation. A new roof on top of old inadequate ventilation will still have ice dams.
Why Illinois Homeowners Call Us
Sundown Exteriors has been working Bloomington-Normal and Peoria roofs through every Illinois winter for years. Locally owned, GAF and Owens Corning trained, BBB accredited, fully licensed and insured. We do steam-based ice dam removal that protects the shingles, and we install the ventilation and insulation upgrades that prevent the next one.
Book a Free Ice Dam Assessment
If ice dams hit your home this winter, or you want to prevent them next year, the cheapest move is a free professional assessment. We inspect the roof, attic, ventilation, and insulation and tell you straight what’s driving the problem.
Two easy ways to get started:
We service Bloomington, Normal, Peoria, and the surrounding Central Illinois metro.