Roof Replacement & Installation in Ontario
Roof replacement means stripping the old roofing material down to the deck (or in some cases overlaying, though most reputable contractors in Mississauga will recommend a full tear-off), repairing any damaged sheathing, installing new underlayment and ice-and-water shield, then laying new shingles, flashing, and ventilation components. It's a bigger job than a repair: expect a crew on site for one to three days depending on roof size and complexity, plus a dumpster or disposal trailer parked out front for the old material. This category covers the 10 businesses in Mississauga that handle full roof replacements and new installations, from single-family homes to larger residential properties.
What to look for before you hire
A few things separate a solid re-roof from a callback-prone one. Check that the contractor is licensed and carries liability insurance and WSIB coverage, since roofing work involves real fall risk and you don't want to be on the hook if someone gets hurt on your property. Ask what underlayment and ice-and-water shield they use, especially around eaves and valleys, since Mississauga winters put real stress on that detail. Get a written estimate that spells out material brand and grade, tear-off and disposal, flashing and vent work, and warranty terms (both the manufacturer's shingle warranty and the contractor's labor warranty are worth confirming separately). Ask how they protect siding, gutters, and landscaping during the tear-off, and whether they'll show you photos of the deck once the old roof is off, since hidden rot or damage is common and should be flagged before it's covered up.
How our scoring works
We rank the 10 contractors in this category using a consistent set of factors, weighted the same way for every business so you can compare fairly. That includes things like review volume and rating trends, responsiveness, and how consistently a contractor delivers on the basics buyers care about. The full breakdown of what goes into the score and how we weight each factor is on our methodology page. For the ranked list of all 10 contractors with their scores, see the best roofing contractors in Mississauga guide.
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All roof replacement & installation, ranked by score and relevance
131 businesses. The order weighs each business's overall score by how much of its reviewed work is roof replacement & installation, so a lower-scored specialist can rank above a higher-scored generalist. Filter and sort below, or open the full map view.
When you submit a quote or contact form through this site, your enquiry may be shared with partner providers who can do the work. We may earn a referral fee from these partners, but our rankings and scores are determined solely by our published method and are never affected by referral fees.
Common questions about roof replacement & installation
- How much does a roof replacement cost in Mississauga?
- It depends heavily on roof size, pitch, material, and how much of the deck needs repair, so get at least two or three written quotes for your specific roof rather than relying on a general number. Asphalt shingle re-roofs are typically the most affordable option, while metal, cedar, or slate cost significantly more per square. The estimate should break out material, labor, tear-off and disposal, and any deck repair as separate line items so you can see where the money goes.
- How often does a roof need to be replaced?
- Standard asphalt shingle roofs generally last 20 to 25 years in Southern Ontario's climate, though that range shortens if the original installation had poor ventilation or the roof has taken repeated ice and wind damage. Premium architectural shingles, metal, and other materials can last longer. If your roof is approaching 20 years old or you're seeing granule loss, curling shingles, or daylight through the attic boards, it's worth getting an inspection.
- What should I expect during the replacement process?
- After the contract is signed, expect a scheduled start date, delivery of materials and a dumpster shortly before work begins, then one to three days of tear-off and installation depending on roof size and weather. A good crew will inspect the deck once the old shingles are off, flag any rot or damage before covering it, and do a final walkthrough with you (including a magnetic nail sweep of the yard) once the job wraps.
- How can I judge the quality of a finished roof job?
- Look for straight, consistent shingle lines, properly sealed and flush flashing around chimneys, vents, and valleys, and no visible nail heads or exposed fasteners. Check that ridge and soffit vents were installed or upgraded, since poor attic ventilation shortens shingle life. Ask for photos of the deck before it was covered, and confirm in writing what the labor warranty covers and for how long, separate from the manufacturer's material warranty.
Guides to choosing roof replacement & installation
- What to expect during a roof replacement in Ontario, step by step
A walkthrough of a typical Ontario roof replacement, from the first inspection to cleanup, so you know what happens and when.