Why Ice Dams Form on Denver Roofs (and How to Prevent Them)
Why Ice Dams Form on Denver Roofs
The Winter Problem No One Talks About
If you’ve lived in Denver for a few winters, you’ve probably noticed those big icicles hanging off the edges of roofs in your neighborhood. A lot of folks think they’re harmless or even pretty. But if those icicles are hanging from your roof, it could mean you’re dealing with an ice dam — and that’s no small problem.
I’ve been roofing in Denver since the 70s, and I can tell you: ice dams are silent destroyers. They sneak up in January, and by spring you’re staring at stained ceilings, rotten wood, or insulation so wet it’s worthless. The frustrating part? Ice dams don’t come from “bad luck.” They come from very specific conditions you can control.
What’s Really Happening Up There?
Think about your roof in winter like a freezer with a space heater sitting inside it. When your attic leaks heat, the snow on your roof starts melting from the top down. That water runs to the edge, hits the overhang where it’s colder, and freezes solid.
Layer after layer builds until you’ve got a mini glacier at the edge of your roof. Behind it, liquid water pools up, looking for any crack or nail hole to sneak into. That’s when the real trouble starts.
Why Denver Homes Are Prone to Ice Dams
Ice dams aren’t just a “cold weather problem.” They’re worse here in Denver for a few reasons:
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Altitude + Sun: At a mile high, our sun is intense. Snow melts on a sunny day even when it’s below freezing. Then it refreezes that night. Perfect ice dam conditions.
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Temperature Swings: One afternoon it’s 40°F, that night it’s 10°F. That daily swing keeps ice dams growing.
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Older Housing Stock: Many Denver bungalows, ranches, and even 90s builds don’t have the attic ventilation modern codes require.
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Neglected Gutters: I see more clogged, sagging gutters in fall inspections than I’d like to admit. By winter, they’re ice dam factories.
The Hidden Damage Ice Dams Cause
Homeowners usually notice ice dams when water stains show up on the ceiling. By that point, the damage is already layered in:
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Decking Damage: Plywood soaks up water, warps, and weakens.
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Insulation Collapse: Wet insulation doesn’t insulate — it just sits heavy and moldy.
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Drywall & Paint: Brown rings, bubbling paint, and crumbling plaster inside your home.
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Fascia & Soffits: Wood trim swells, cracks, and peels from trapped moisture.
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Mold Risk: Damp attics become breeding grounds for mold spores that spread fast.
I’ve been on jobs where a single winter’s ice dam damage cost more than a brand-new roof would have.
Prevention: What Works in Denver Homes
Here’s what I tell homeowners who want to stop ice dams before they start:
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Clean Gutters in Fall
This one’s basic but overlooked. If your gutters are packed with leaves when the first snow hits, melt water has nowhere to go. -
Ventilate the Attic
Cold attics = long-lasting roofs. Proper ridge vents and soffit vents keep your roof deck close to outside temps, stopping uneven melt. -
Insulate the Attic
Heat belongs in your living space, not your attic. Extra insulation keeps the attic cool and your energy bill lower. -
Install Ice & Water Shield
Denver code requires it at eaves, but older roofs may not have it. This underlayment buys you protection if dams form. -
Consider Heat Cables
They’re not my first choice, but in problem areas (north-facing valleys or shaded eaves), heat cables can keep a channel open for meltwater.
What NOT to Do if You See an Ice Dam
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Don’t take a shovel or axe to it — I’ve seen homeowners destroy shingles this way.
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Don’t pour rock salt — it kills landscaping and corrodes gutters.
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Don’t ignore it — “waiting for spring” just means more water gets in.
Call a pro for safe removal and then address the root causes: insulation, ventilation, and drainage.
Real Story: The $300 vs. $8,000 Lesson
I had a client in Englewood who skipped fall gutter cleaning. By February, ice dams formed over two bedrooms. The ceiling drywall collapsed after a melt-freeze cycle, and the attic insulation was ruined.
That $300 gutter job turned into $8,000 worth of repairs. A painful but preventable lesson.
Conclusion: Stop Ice Dams Before They Start
Ice dams aren’t inevitable. They’re a sign your roof system isn’t balanced — and fixing that balance protects your home for years to come.
At Ernie’s Roofing, we know Denver winters better than anyone. We’ll inspect your roof, attic, and gutters, and give you straight answers. If you need a repair, we’ll say so. If you need upgrades, we’ll explain why. Call 720-346-ROOF today and get ahead of ice dam season.
FAQs
What’s the number one cause of ice dams in Denver?
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Attic heat escaping through poor insulation.
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Snow melting unevenly and refreezing at eaves.
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Gutters clogged with fall debris.
Can ice dams ruin a brand-new roof?
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Yes, if ventilation and insulation are poor.
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New shingles can’t stop backed-up water.
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System design matters more than shingle age.
Are ice dams covered by insurance?
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Often yes, if they cause interior water damage.
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Coverage varies — cosmetic issues aren’t always included.
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Documentation from a roofer helps with claims.
Do gutter guards prevent ice dams?
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They help by reducing clogs.
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But ventilation and insulation are still critical.
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Gutter guards are part of the solution, not the whole fix.
Should I knock down icicles?
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Not unless they’re dangerous to people walking below.
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Icicles are just the symptom — the real problem is the dam behind them.
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Focus on prevention, not smashing ice.
Do heat cables waste electricity?
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They do use power, but only when snow is present.
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They’re most effective on problem spots, not whole roofs.
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Better insulation saves more money long term.
How often should I check my attic in winter?
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Once a month is smart during snow season.
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Look for frost, wet spots, or uneven insulation.
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Early signs inside the attic prevent bigger headaches.
Can flat roofs get ice dams?
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Yes, but they form differently.
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Flat roofs pool water, which then freezes and expands.
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Regular maintenance is even more critical on flat systems.
How much does ice dam prevention cost in Denver?
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Gutter cleaning: $200–$400.
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Ventilation upgrades: $500–$1,500.
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Attic insulation: $1,500–$3,500.
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Compare that to $5,000+ in repair bills.
Why trust Ernie’s Roofing for ice dam solutions?
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We’ve been fixing Denver homes since 1978.
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We know local codes, climate, and insurance requirements.
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We give straight answers: repair if possible, replacement only if needed.
Ernie’s Roofing – Your Denver Roofing Contractor
Ernie’s Roofing
1195 W Custer Pl
Denver, CO 80223
Phone: 720-346-ROOF
Website: https://erniesroofing.com/
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