Short answer, roof heating cables can help with ice dams in Ottawa, but on their own they rarely fix the problem. They work best as a backup in a few trouble spots, not as the main defence against our winters. Here is what we see on Ottawa roofs every winter, and what tends to work better.
What Are Roof Heating Cables?
Roof heating cables go by a few names, including heat cables, heat tape, heat trace and roof de-icing cables. They are electric cables clipped along the eaves in a zigzag pattern, and often run through the eavestroughs and down the downspouts.
The cables give off controlled heat that melts narrow channels through the snow and ice. The goal is not to clear the whole roof, but to give meltwater a path off the roof and into the eavestroughs, so it is less likely to back up under the shingles and leak into the house.
They are built to manage water flow, not to keep your roof or eavestroughs free of snow.
Do Heating Cables Work in Ottawa’s Climate?
Installed properly, good-quality roof heating cables can reduce ice dam problems in certain spots. But during roof inspections across Ottawa, we regularly see homes that still get ice dams with cables already on the roof.
The reason is our winters. Heavy snowfall and long stretches of deep cold mean there is simply too much snow and ice for a cable to keep up with. The cables are designed to run at safe temperatures, because more heat could damage shingles, roof membranes or eavestroughs.
So in a hard Ottawa winter, heat cables give limited protection, especially on roofs where the real cause is an insulation or ventilation problem in the attic.
Where Heat Cables Help Most
- Short sections of eave over an unheated porch or entry that always ice up
- Roof valleys where two slopes meet and meltwater collects
- Eavestroughs and downspouts that freeze solid and overflow, especially on the north side of the house
- Older homes where fixing the attic right away is not possible
If cables are already on your roof, they need to be clipped on properly, run into the eavestroughs and downspouts so meltwater has somewhere to go, and checked each fall for damage. Clogged eavestroughs make every ice dam worse, cables or not.
Do We Install Heat Cables?
Yes. We install roof heating cables along eaves, valleys, eavestroughs and downspouts, and we will be straight with you about what to expect. In our experience they are hit or miss. Sometimes they solve the problem, sometimes they do nothing, and occasionally they make it worse by refreezing water in the wrong spot. We have also seen them work very well on the right roof, so we look at your attic and roof first and tell you honestly whether cables are worth it.
Signs the Real Problem Is in Your Attic
- Ice dams form all along the eaves, not just in one spot
- Snow melts off the roof quickly while your neighbours’ roofs stay white
- Icicles hang along most of the house
- Frost or damp spots on the underside of the roof deck in the attic
All of these point to heat escaping from the house into the attic and warming the roof deck from below.
Long-Term Fixes That Work Better Than Heat Cables
In most homes, better attic insulation and proper roof ventilation do more than heating cables ever will. Insulation keeps the heat in the house, and ventilation keeps the roof deck cold and even, which stops the melt and refreeze cycle that builds ice dams in the first place.
In tougher cases, the best fix is a re-roof with a full ice and water protection membrane, such as Grace Ice & Water Shield, along the eaves and valleys. That extra layer keeps water out even when an ice dam does form. And when heavy snow piles up, safe roof snow removal takes the load off before it turns into ice.
Our Recommendation
Heating cables can be part of an ice dam plan, but in Ottawa they should not be the whole plan. Fixing insulation, ventilation and roof protection gives you more reliable, longer-lasting results.
Need ice dams cleared right now? We carve channels through the ice and use roof melt to get the water moving, without hammering at your shingles. See our ice dam removal service.
If you get ice dams every winter, a professional roof inspection will show where the heat is escaping and what will actually fix it. Our basic roof and attic inspection is free.
