Roof Replacement in Thunder Bay
Complete roof replacement for Thunder Bay homes, built for heavy snow load, ice dams, and Lake Superior weather, with proper ventilation and ice-and-water protection.
A New Roof Built for the North
Replacing a roof in Thunder Bay is not the same job as replacing one in southern Ontario, and it should not be priced or built like one. Our roofs face heavy snow load that sits for months, repeated freeze-thaw cycles, and cold wind off Lake Superior. A replacement done right up here is a chance to fix the underlying problems that wear roofs out, not just to lay down new shingles and hope for a better outcome.
Sleeping Giant Roofing replaces roofs across Thunder Bay, both the Port Arthur and Fort William sides, and out into Oliver Paipoonge, Shuniah, and the surrounding townships. Call (807) 501-9192 for a free assessment.
When Replacement Beats Repair
A full replacement is the right call when your roof is past its serviceable life or failing in more than one place. The signs to watch for on a Thunder Bay home include:
- An asphalt roof past 15 to 20 years, given how hard our climate is on shingles.
- Widespread curling, cupping, or heavy granule loss across the shingles.
- Repeated ice-dam leaks every winter, not just an isolated spot.
- Sagging, soft spots underfoot, or daylight visible in the attic.
- Multiple old layers of shingles that have to come off.
If the damage is isolated to one slope and the roof is otherwise sound and young, a roof repair is usually the smarter spend. We will tell you honestly which way to go. A roof inspection is the way to be sure.
How We Replace a Roof
Tear-Off to a Sound Deck
We strip the old roofing right down to the deck rather than laying over it. On older Thunder Bay homes that often means removing two or more layers. Tearing off lets us see and fix what is underneath, which is where the real problems usually hide.
Decking Repair
With the old roofing gone, we inspect the plywood sheathing and replace any that is soft or rotted. Eave and valley rot from years of ice damming is common here, and a new roof is only as good as the deck it sits on.
Ice-and-Water Membrane and Underlayment
We install a self-adhering ice-and-water membrane along the eaves, in the valleys, and around penetrations. In a freeze-thaw climate like ours this is the critical secondary defence against ice dams, and it is not optional on a roof built for Thunder Bay. A full synthetic underlayment goes over the rest of the deck.
Ventilation Correction
This is the step that separates a roof that lasts from one that dams up every winter. We rebuild the attic intake and exhaust ventilation so the deck stays cold, which stops heat from melting the snowpack and feeding ice at the eaves. Most ice-dam problems on older homes trace back to ventilation, so we fix it here. This often ties in with soffit and fascia work.
New Roofing Material
We install your chosen system, whether that is cold-climate architectural shingles or a metal roof, to the manufacturer’s specification, with proper flashing at every transition, chimney, and penetration.
Cleanup
We protect your property during the work and leave it clean, magnet-sweeping the yard for nails and hauling away all the old material.
Choosing Your Material
For most Thunder Bay homeowners the real decision is asphalt versus metal. A quality architectural shingle is a sound mid-budget choice and, installed with full membrane and good ventilation, holds up well. Metal costs more up front but sheds snow, beats the wind, and lasts decades longer in our climate, so for anyone planning to stay it is often the better long-term value. Our guide on metal versus asphalt for Thunder Bay winters walks through the trade-offs, and the roof cost calculator gives you a quick ballpark.
Get a Free Replacement Estimate
We will inspect your roof, talk through your options without pressure, and give you a clear written estimate. Call (807) 501-9192 or request a free estimate online. We serve all of Thunder Bay and Northwestern Ontario.
How It Works
Free Consultation & Inspection
Give us a call or fill out our online form. We will come to your property, inspect your roof thoroughly, and discuss your options, all at no cost and no obligation.
Detailed Written Estimate
You will receive a clear, itemized quote that covers materials, labour, timeline, and warranty details. No hidden fees, no surprises, just honest pricing.
Expert Installation
Our experienced crew handles your project from start to finish with quality materials and clean, professional workmanship. We keep you updated every step of the way.
Final Walkthrough & Warranty
Once the job is done, we walk through everything with you to make sure you are completely satisfied. You get a written warranty so your investment is protected for years to come.
Frequently Asked Questions
How do I know if my Thunder Bay roof needs replacing instead of repairing?
If your asphalt roof is past 15 to 20 years, has widespread curling or granule loss, or you are getting repeated ice-dam leaks every winter, replacement is usually the better value than chasing repairs. The Thunder Bay climate is hard on roofs, so they often reach end of life at the lower end of their rated range. A roof under 12 years old with damage on a single slope is more likely a repair. We give you an honest assessment either way.
What is the best time of year to replace a roof in Thunder Bay?
Our roofing season is shorter than the south, so the prime window runs from late spring through fall when the deck is dry and temperatures are workable. That said, we replace roofs across more of the year than people expect, including cold-weather installs where conditions allow. If your roof is failing in winter, we can tarp and stabilize it and plan the full replacement for the next workable window.
Will you fix the ventilation and ice-dam problems during a replacement?
Yes, and on a Thunder Bay roof that is the whole point. A replacement is the best chance to correct the underlying causes of ice damming: undersized attic ventilation and missing ice-and-water membrane. We install membrane at the eaves and valleys and rebuild the intake and exhaust ventilation so the deck stays cold. Just laying new shingles over the same old problems means the same leaks come back.
How long does a roof replacement take?
Most residential replacements in Thunder Bay take one to three days, depending on the size of the home, how many old layers come off, and the weather. Larger or steeper roofs, and jobs that turn up decking rot, can run longer. We give you a realistic timeline with your written estimate and keep you updated as the work goes.
What happens if you find rotted decking under my old roof?
We replace it. Decades of ice damming and trapped attic moisture can rot the plywood sheathing, especially along the eaves and in valleys, and this is common on older Thunder Bay homes. Once the old roofing is off we inspect the deck and swap out any soft or rotted sheathing before the new roof goes on. Building over bad decking is the kind of shortcut that comes back as a leak.