Calgary ice dams — root cause, real fixes.

What an ice dam actually is

Warm air leaks into your attic from the heated house below. That warm air melts the snow on the upper part of your roof. The melt-water runs down to the eaves — which are not warmed by the attic — refreezes there, and forms a ridge of ice. The next round of melt-water hits that ridge, has nowhere to go, and backs up under your shingles into the home.

It looks like the shingles are leaking. They’re not. The roof is doing exactly what it was designed to do; the problem is warm-air leakage and inadequate insulation.

Why heat cable is a band-aid

Heat cable on the eaves does work — it melts a channel through the ice dam so water can drain. But it’s expensive to run, it doesn’t address the cause, and it adds another point of failure.

The right fix is to stop the warm air leakage in the first place.

The three real fixes, in order

1. Air-seal the attic floor. Recessed pot lights, plumbing penetrations, attic hatch — these are the leak points. A typical Calgary attic air-seal is $1,200–$2,400 of work that pays back in heating cost and ice dam elimination.

2. Top up attic insulation to R-60. Calgary code-minimum on new builds is R-50. Most older Calgary homes are at R-30 to R-40. Bringing it to R-60 with blown cellulose is roughly $1,800–$3,500.

3. Ensure intake and exhaust ventilation are balanced. Most Calgary attics are under-ventilated and especially under-supplied on the intake (soffit) side. Continuous ridge vent + continuous soffit intake with baffles is the standard upgrade.

When you should bring in a roofer

If you’ve had ice dam water inside the home, the damage chain is: insulation gap → ice dam → water back-up → underlayment failure → shingle damage → drywall stain. Address each link.

We don’t install insulation, but we partner with Calgary insulation contractors we trust. If you call us about ice dams, we’ll diagnose the chain end-to-end and tell you which contractor to call for which fix.