Ice dams are one of the most common winter roof problems in Eastern Ontario, and one of the most preventable. From Ottawa and Brockville to Perth, Carleton Place and the rest of Lanark County, we see the same pattern every year: a heavy snowfall, a few mild days, a hard freeze, and suddenly water is coming through a ceiling.
Left alone, an ice dam can cause leaks, mold, damaged insulation and costly repairs. At Kovar Contracting, we’d rather help you stop it before it starts. Here’s what causes ice dams, the warning signs to watch for, and how to protect your home this winter, including when heat trace cables are the right fix.
What Is an Ice Dam?
An ice dam is a ridge of ice that forms along the bottom edge of your roof. It happens when snow melts on the warmer upper part of the roof, runs down, and refreezes at the colder eaves.
Over time that ice builds into a barrier, or “dam,” that stops meltwater from draining. The trapped water has nowhere to go, so it backs up under your shingles and into your roof deck, attic and walls.
What Causes Ice Dams?
Ice dams come down to one thing: uneven roof temperatures. The upper roof is warm enough to melt snow while the eaves stay below freezing. The most common causes are:
- Poor attic insulation. Heat escapes from your living space into the attic and warms the roof deck from below.
- Poor attic ventilation. Without enough airflow, warm air gets trapped in the attic and raises roof temperatures.
- Heavy snow accumulation. A thick layer of snow insulates the roof, holding in warmth underneath while the overhanging eaves stay cold.
- Clogged eavestroughs and gutters. Leaves and debris trap water that freezes and gives ice a place to build.
Signs You Have an Ice Dam Problem
Catching an ice dam early can save you from expensive interior damage. Watch for:
- A thick ridge of ice along the edge of your roof
- Large icicles hanging from the eaves (big icicles are often the first visible sign of an ice dam)
- Ice building up inside your eavestroughs or downspouts
- Water stains, peeling paint or bubbling drywall on ceilings or upper walls near exterior walls
- Damp or frosty spots in the attic
The Risks of Ignoring Ice Dams
An ice dam rarely stays a small problem. If it isn’t addressed, it can lead to:
- Roof leaks. Water trapped behind the dam seeps under shingles and into your home.
- Mold and mildew. Ongoing moisture in the attic and walls creates ideal conditions for mold, which affects indoor air quality.
- Eavestrough damage. The weight of the ice can pull eavestroughs and gutters away from the house.
- Damaged insulation. Wet insulation loses much of its effectiveness, which means more heat loss and higher energy bills.
- Falling ice. Large icicles and ice chunks are a real hazard for anyone walking below.
How to Prevent Ice Dams
The best prevention keeps your whole roof cold and even, so snow doesn’t melt and refreeze at the edges.
- Improve your attic insulation. Good insulation keeps your home’s heat where it belongs, out of the attic. Learn more about our attic insulation services.
- Improve attic ventilation. Proper airflow keeps the roof deck close to the outdoor temperature.
- Clean your eavestroughs in late fall. Clear gutters give meltwater a path to drain.
- Install heat trace cables in problem areas. More on this below.
- Book a professional roof inspection. A contractor can spot insulation, ventilation and roofing issues before winter arrives.
How Heat Trace Cables Prevent Ice Dams
Insulation and ventilation address the root cause, but some roofs have trouble spots that keep forming ice no matter what. Low-slope sections, roof valleys and eaves over unheated overhangs are the usual culprits.
Heat trace cables, also called roof heating cables, are installed in a zigzag pattern along these areas and inside eavestroughs and downspouts. They keep a clear channel open so meltwater drains away instead of backing up under your shingles. The system plugs into a dedicated outdoor GFCI outlet, and we supply a duty-cycle timer that cycles the cables on and off to keep power use down.
They can go in any time the eavestroughs aren’t frozen, and they need to be in before the first hard freeze. Kovar Contracting installs Heat-Line Paladin, a commercial-grade self-regulating heat trace system, across Ottawa, Perth, Carleton Place, Brockville and Lanark County, and our roofing work has been featured on Home RenoVision DIY.
How do I know if I have an ice dam?
Look for a thick ridge of ice along the edge of your roof, large icicles hanging from the eaves, or ice building up inside your eavestroughs. Water stains on ceilings or upper walls mean meltwater is already getting in.
Are icicles on my roof a sign of an ice dam?
Often, yes. A few small icicles are normal, but large icicles along the eaves usually mean snow is melting higher on the roof and refreezing at the edge. If you’re seeing big icicles every winter, it’s worth having your attic insulation and ventilation checked.
Are ice dams dangerous?
Yes. Trapped water can leak into your walls and ceilings and cause mold, rot and damaged insulation. Heavy ice can pull eavestroughs off the house, and falling icicles and ice chunks are a real hazard for anyone walking below.
Should I chip ice off my roof?
No. Hammering, chipping or prying at ice dams can crack shingles, damage eavestroughs and void roofing warranties. Climbing onto an icy roof is also dangerous. If an ice dam is causing a leak, call a professional.
How do you safely remove an ice dam?
For ice that’s already built up or is causing a leak, professional removal is the safest option. It avoids damage to your shingles and eavestroughs.
Can I use salt to melt an ice dam?
Avoid rock salt (sodium chloride). It can damage shingles, corrode metal eavestroughs and flashing, and harm plants below. Calcium chloride ice melt is gentler, but it’s still a short-term fix. It does nothing about the heat loss causing the dam.
Do clogged eavestroughs cause ice dams?
Clogged eavestroughs don’t cause ice dams on their own, but they make them worse. Leaves and debris trap water that freezes and gives ice a place to build. Cleaning your eavestroughs in late fall is a simple way to reduce the risk.
Will more attic insulation stop ice dams?
Often, yes. Good insulation combined with proper attic ventilation keeps the roof cold and even, which is the most effective long-term prevention. Learn more about our attic insulation services.
Do heat trace cables work?
The right ones do, when they’re installed correctly in the right spots. Not just any cable will do, and off-the-shelf kits from a hardware store are no match for a commercial-grade system like the Heat-Line Paladin cable we install. The right cables keep a clear path open along eaves, valleys and inside eavestroughs and downspouts, so meltwater drains instead of backing up under shingles. They treat the symptom, though. Insulation and ventilation are the cure, and heat trace is the last resort for trouble spots that keep icing up.
When should heat trace cables be installed?
Any time the eavestroughs and downspouts aren’t frozen. Treat fall as the deadline: the cables need to be in before the first hard freeze. Installing them on an icy, snow-covered roof is harder, riskier and sometimes impossible. Book early, too: in the fall, cable orders can run two to three weeks out.
Can heat trace cables be installed on any roof?
Most asphalt shingle and metal roofs can be fitted with heat trace cables. The right layout depends on your roof’s pitch, problem areas and eavestrough setup. A contractor should assess the roof first so the cables go where ice actually forms.
Do I need an electrician for heat trace cables?
Usually, yes. The system needs a dedicated GFCI outlet near the downspout, and an electrician has to install it. That work is usually separate from our heat trace quote, so plan for it when you budget. We supply a duty-cycle timer with the system, which cycles the cables on and off to keep power use down.
Are ice dams covered by home insurance?
It depends on your policy. Some policies cover water damage from ice dams, while others treat prevention as homeowner maintenance. Check with your insurer, and document any damage with photos as soon as you notice it.
Protect Your Home Before the First Freeze
At Kovar Contracting, we help homeowners across Ottawa, Perth, Carleton Place, Brockville and Lanark County keep their roofs safe, efficient and built to last. Our team can assess your roof, attic insulation and ventilation, and recommend the right fix for your home, whether that’s prevention, heat trace installation or repairs.
Don’t wait for the first leak.
Call us at 613-979-1704 or contact us online to book your roof assessment before winter sets in.