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Ice dams and roof snow in Kitchener: when should snow removal include the roof?

An ice dam forms when heat escaping into the attic melts the underside of the snow on the roof, and the meltwater refreezes at the cold eave. For most Kitchener homes the fix is in the attic, not on the roof, and clearing roof ice by hand is a job for a professional with the right equipment, not a plow crew with a ladder.

Last updated October 24, 2026 · Reviewed by the Kitchener Snow Removal team

What causes ice dams on a Kitchener roof?

Ice dams are caused by heat from the attic melting the bottom of the snow on the roof, according to the Canada Mortgage and Housing Corporation. When outside temperatures sit just below freezing, roughly 0 to -10 C, water runs down the roof under the snow blanket and freezes when it reaches the unheated overhang at the eave. The ridge of ice that builds there is the dam. Water backing up behind it finds its way under the shingles and into the roof space, and from there into the insulation, the soffit and eventually the ceiling or wall below.

Kitchener's winter spends a lot of time in exactly that temperature band. The Environment Canada climate normals for the Region of Waterloo airport in Breslau put the mean daily temperature at about -3 C in December and -6.5 C in January, with roughly ten days of freezing rain or drizzle a year on top. A week of -4 C days after a 20 cm storm is ice dam weather, and the houses that suffer are the ones losing the most heat into the attic.

Signs you have an ice dam, not just icicles

• A thick band of ice along the eave, well above the gutter, with icicles hanging from it.
• Icicles forming behind the gutter or along the soffit, not just off the gutter lip.
• Water stains or dampness on a ceiling or exterior wall near the eave, usually after a milder day.
• Ice building up in a valley, behind a chimney or around a skylight, which is where CMHC found most ice collected during the 1998 ice storm.
• Bare patches of roof mid-slope while the eaves stay snow-covered, which shows where the attic heat is escaping.

Shaded north and east slopes in older neighbourhoods such as Forest Heights and the century homes around downtown Kitchener are the typical cases, because the snow never clears and the attics were insulated to a very different standard.

What is safe to do yourself

CMHC's advice is blunt: no ice problem on your roof is serious enough to risk broken bones. From the ground, the reasonable steps are:

1. Pull loose snow off the lower metre or two of the roof with a roof rake while standing on the ground. Taking the snow away removes the water supply for the dam. Work from the eave upward and keep clear of the overhead hydro service and of anything that could fall.
2. Keep the gutters and downspouts flowing where you can reach them safely, so meltwater has somewhere to go on a mild day.
3. Make a drainage path, not a clean roof. CMHC's research after the 1998 storm found that drainage, not removal, solved the problem in most cases. A channel through the dam that lets water off the roof is enough; stripping the eave to bare shingle is what causes damage.

Things CMHC warns against: hacking at ice with hammers, axes, shovels or scrapers, which damages shingles and can rip them off as freed ice slides; chemical de-icers scattered over the roof, which can discolour shingles, break down membranes and corrode flashings and drains; and getting on a snow-loaded sloped roof at all. CMHC notes that removing ice will probably invalidate your shingle warranty and says that if ice must be removed, it should be done by a professional with proper equipment and training.

Does snow removal include the roof?

Not as a routine service, and you should be cautious of a driveway contractor who offers it as one. Working on a snow-loaded roof is a different trade from clearing a lot. The contractor we book for Kitchener treats roof snow and ice dam calls case by case: tell them what you are seeing, ice at the eaves, water inside, a heavy load on a low-slope garage or porch roof, and it is either handled with the right equipment or referred to someone set up for roof work. A plow crew does not go up a ladder, and a contract for driveway and walkway clearing does not include the roof unless the written scope says so.

Most sloped roofs in Kitchener never need the snow removed for weight reasons; the problem is water, and a drainage path handles it. The exceptions, drawing on CMHC's guidance:

• Low-slope or flat roofs on additions, garages and porches, where ice from freezing rain can approach the thickness CMHC flags as a weight concern (around 15 cm, or six inches, of solid ice).
• Signs of structural stress inside the house: interior doors that start to jam, new cracks in drywall or plaster near the centre of the house, or a visible sag along the ridge. If those change from day to day during a storm, reduce the load and get an inspection.
• Active leaking that a drainage channel has not stopped.

Water leaks on their own are expensive but, as CMHC puts it, do not necessarily indicate a structural problem requiring total clearing of the roof.

The permanent fix is in the attic

CMHC describes the first line of defence against ice dams as reducing the attic temperature by stopping air leaks from the house below and adding enough insulation to the attic floor. Heating cables and other de-icing techniques are a last resort. In practice that means sealing around pot lights, the attic hatch, plumbing stacks and bathroom fan ducts, topping up insulation to current Ontario levels, and making sure soffit vents are not buried so cold outside air can move through the attic. A home that stops forming ice dams in February is a home that is also losing less heat in January, so the fix pays twice.

What this means for your winter plan

Book the driveway and walks on a seasonal contract, keep a roof rake by the door for the lower edge of the roof, and get an attic assessment before next winter if you had icicles the size of your arm this one. If you see water inside or a load on a flat roof you are not comfortable with, describe it here and the Kitchener contractor will tell you straight whether it is something they handle or a referral. Planning ranges for the ground-level work are on the Kitchener snow removal cost page.

Sources

• Removing ice on roofs (About Your House CE15) - Canada Mortgage and Housing Corporation, via Government of Canada Publications
• Climate normals 1981-2010, Waterloo Wellington A - Environment and Climate Change Canada
• Snow and ice - City of Kitchener