Ice Dams and Roof Repair in Winnipeg: Why the Attic Is the Problem and What a Roofer Can Fix

Ice dam or roof leak?

An ice dam forms when heat escaping into the attic warms the roof deck, snow melts from underneath, and the meltwater refreezes when it reaches the cold overhang at the eaves. Water pools behind the ridge of ice, backs up under the shingles and comes through the ceiling or down the inside of an exterior wall, often days into a cold spell and nowhere near where you would expect a roof leak. A true roof leak shows up during or after rain or a thaw, usually below a valley, a chimney, a vent or a damaged area, and it appears in the same place each time.

Look outside: thick icicles and a band of ice along the eaves, with the roof above bare or thin, mean the attic is losing heat. A roof that stays uniformly snow-covered is a well-insulated roof.

What the attic fix involves

The order is air sealing first, then insulation, then ventilation. Warm air leaks into Winnipeg attics through pot lights, the attic hatch, plumbing stacks, top plates and bathroom fans that were never ducted outside. Sealing those with foam and gaskets does more than adding insulation on top of them. Then insulation to current Manitoba levels, which are far above what a 1950s bungalow was built with, and clear soffit and roof ventilation so the attic stays as cold as the outdoors. A contractor should measure the existing depth, find the leaks with a thermal camera or a smoke pencil, and quote all three.

Efficiency Manitoba has offered rebates for insulation upgrades, and the same work cuts heating bills through the longest winter in urban Canada. Ask the contractor whether they are registered with the program and what the current terms are.

• Photos of icicles, the ice band and the interior stain
• Attic insulation depth and type
• Bathroom and kitchen fans confirmed vented outside
• Soffit and roof vents present and unblocked
• Current Efficiency Manitoba program terms

When a roofer is the right call

A roofer fixes what the water damaged and what the roof was missing: shingles lifted by the ice, flashing torn at valleys, and, during a replacement, an ice-and-water membrane along the eaves and in the valleys that limits how far a dam can push water in. That membrane is now standard on a Winnipeg re-roof; ask how far up the slope it will run. A roofer cannot fix the attic, and a new roof over a leaky attic will grow the same dams.

Whether a re-roof needs a building permit in Winnipeg depends on what changes; like-for-like re-shingling is generally treated differently from deck or structural work. Ask the roofer and confirm with the City. Roofing is unlicensed in Manitoba, so ask for a certificate of liability insurance and a WCB Manitoba clearance, and keep deposits small under a written contract; the Manitoba Consumer Protection Office handles complaints about contractors.

Clearing snow and ice safely

An active ice dam leak in February needs the dam removed, and the safe way is a professional steam service that melts channels through the ice without touching the shingles. Chipping with an axe or a hammer, spreading salt or de-icer, and pressure washing all damage the roof and shorten its life; heating cables along the eaves keep a channel open but treat the symptom, not the cause. A roof rake used from the ground to clear the first metre or so of snow above the eaves reduces dam formation and is the safe limit for a homeowner. Nobody should be on a Winnipeg roof in winter without fall protection.

Snow load itself is rarely the issue on a pitched Winnipeg roof, but flat and low-slope roofs on commercial buildings and some houses can need clearing after heavy or wet snow. Signs are sticking doors, new cracks and visible sag, and they warrant a same-day call.