Why Edmonton homes get ice dams — and how to stop them
An ice dam is a ridge of ice at the roof edge that traps meltwater behind it. That trapped water backs up under the shingles and comes through your ceiling. Edmonton's long freeze-thaw stretches make it common — but it's caused by heat and drainage inside your house, not by snowfall.
The mechanism, in one paragraph
Warm air escapes from the living space into the attic. The attic warms the roof deck. Snow on the warm upper roof melts, runs down to the cold eave overhang — which has no heated space beneath it — and refreezes. Repeat over several days and you build a solid ice ridge. Any further meltwater ponds behind the ridge and finds its way under the shingle course, then into the soffit, wall cavity or ceiling.
Where clogged eavestroughs come in
Eavestroughs don't create ice dams, but a full trough is the perfect starter kit. Packed wet debris freezes into a solid block at the eave, giving the ice a base to grow on and removing the only drainage path meltwater had.
A frozen downspout does the same thing vertically: water backs up the spout, over the trough lip, and freezes into a column that can tear the trough off the fascia under its own weight.
What actually prevents ice dams
In order of how much difference they make:
- ·Attic air sealing — pot lights, bath fans, plumbing stacks and the attic hatch are the usual leak points. This is the single biggest fix.
- ·Attic insulation to current levels (R-50 or better for Edmonton). Under-insulated 1960s–80s attics are the most common ice dam homes we see.
- ·Working soffit and ridge ventilation so the roof deck stays close to outdoor temperature.
- ·Clean eavestroughs and clear downspouts going into freeze-up, so meltwater has a path out.
- ·Clear roof valleys — a blocked valley pushes meltwater sideways under the shingles.
- ·Bath and dryer vents that terminate outside, not into the attic.
What doesn't work (or makes it worse)
We get called after these more often than we'd like.
- ·Chipping ice off with a hammer, hatchet or ice pick — this shatters cold shingles and punctures troughs.
- ·Road salt or ice-melt tablets tossed in the trough — corrodes aluminum, kills landscaping, and only bores a small hole.
- ·Running a torch or heat gun at the eave. Yes, people do it. It causes fires.
- ·Heat cable alone with no attic work. Cable manages symptoms and adds an electrical bill; it doesn't fix the heat loss.
If you already have one this winter
The goal is to relieve the pressure without damaging the roof: clear snow from the lower 3–4 feet of the roof with a roof rake from the ground, then create a drainage channel through the dam (a nylon stocking filled with calcium chloride laid across the dam works). Then plan the attic work for spring.
If water is already coming through a ceiling, get the attic inspected — the leak path matters more than the ice.
Common questions
Will cleaning my eavestroughs prevent ice dams?
It removes one major contributing factor and gives meltwater somewhere to go, but the root cause is attic heat loss. Clean troughs plus attic sealing is the combination that works.
Are heat cables worth it in Edmonton?
As a targeted patch on a problem valley or over an entryway, yes. As a whole-roof solution instead of fixing insulation, no.
Do you remove ice dams?
We focus on prevention — fall cleaning, downspout clearing and roof debris removal before freeze-up. For active steam removal we'll point you to a specialist.
When is the deadline to book a fall clean?
Late October. Once troughs freeze solid, nothing can be done until thaw.
Want it handled instead?
Flat-rate eavestrough cleaning across Edmonton, Sherwood Park, St. Albert, Spruce Grove, Leduc, Beaumont and Fort Saskatchewan — with a photo report after every job.