Roof Replacement Cost in Ontario (2026): Why Two Quotes Never Match
Roofers price the roof, not your floor plan. Once you know the unit they use, the quotes become comparable.
In short
A new roof in Ontario runs $8,500 to $22,000 installed. Architectural asphalt shingles — what most houses get — work out to about $5.50 to $8.50 per square foot of roof surface, and standing-seam metal to $11 to $22. In the GTA, asphalt commonly lands between $8,500 and $18,000.
The reason two quotes on the same house can differ by thousands is almost never dishonesty. It is that roofers price roof area, in units of 100 square feet called squares, and your roof is considerably larger than your floor plan once pitch and overhangs are counted. Ask every bid for the number of squares and you can compare them in one line.
Key facts
| Typical Ontario total | $8,500–$22,000 installed |
| Architectural asphalt | $5.50–$8.50 per sq ft of roof |
| Standing-seam metal | $11–$22 per sq ft of roof |
| Cedar shake | $14–$22 per sq ft of roof |
| The unit roofers quote in | A “square” — 100 sq ft of roof surface |
| Typical detached roof | Roughly 18–30 squares |
| Expected life | Asphalt about 25–30 years · metal 40–70 |
How much does a roof cost in the GTA?
Material sets the band; roof area sets where you land inside it.
| Material | Per sq ft of roof | Typical detached house |
|---|---|---|
| Architectural asphalt shingle | $5.50–$8.50 | $8,500–$18,000 |
| Standing-seam metal | $11–$22 | $21,000–$33,000 |
| Cedar shake | $14–$22 | $25,000–$35,000 |
| Complex roofline, steep pitch, dormers | Upper end of any band | Can pass $30,000 |
Note where these numbers come from: roofing companies’ own published cost guides. They are the people selling the work, which does not make the figures wrong — the trade publishes fairly openly — but it is worth knowing whose arithmetic you are reading.
What is a roofing square, and why does it matter?
One square is 100 square feet of roof surface. It is the unit the trade actually works in, and it is the reason quotes look incomparable to homeowners.
A 1,500 square foot bungalow does not have a 1,500 square foot roof. Pitch alone adds surface — a steeper roof covers the same footprint with more material — and then overhangs, dormers and a garage add more. The same house can be 18 squares or 26 depending on its shape.
So ask every roofer for two numbers: how many squares, and the price per square. Two quotes that looked $4,000 apart usually turn out to be measuring different roofs, or including different work. Occasionally one of them measured wrong, and now you know which.
Tear-off or layover?
Tear the old roof off. It costs more and it is the job worth buying.
Laying new shingles over old ones saves the disposal and the labour of stripping, and it buries whatever is wrong with the decking underneath — soft plywood, old leaks, poor ventilation. It also adds weight to a structure that already carries Ontario snow load, and it commonly voids manufacturer warranties.
A quote that is cheap because it is a layover is not the same product as the one beside it. Ask which it is, in writing.
Why the price can move mid-job
Roofing is one of the few trades where the final number honestly cannot be known in advance, because the thing being inspected is under the thing being removed.
Once the old shingles come off, rotten or delaminated plywood shows up. It has to be replaced, and no one could have seen it from the driveway. That is legitimate.
What separates a fair roofer from a bad one is whether the price for it was agreed before the tear-off. A good quote states the cost per sheet of replacement decking up front. A quote that says nothing about it has an open end, and you will be negotiating on a day when your house has no roof.
What should be in the quote
Red flags
What to do next
Get three quotes and ask each one the same two questions: how many squares is my roof, and what do you charge per sheet if the decking is rotten. Those two answers turn three incomparable numbers into a real comparison.
Compare renovation and construction companies in Ontario on Ontario24 and contact roofers directly. Ontario24 is a classified directory — we help you find and compare businesses, and we do not vet them, so ask for WSIB clearance and proof of liability insurance yourself; our safety tips cover the rest.
While the roof is being priced, the connected jobs are worth pricing too: our eavestrough guide covers the drainage the roof depends on, and our building permit guide explains when re-roofing crosses into permit territory.
Before you call anyone, it helps to know what this job should cost and what the next one will. What things cost in Ontario in 2026 puts 75 service prices in one table.
Frequently asked questions
Between $8,500 and $22,000 installed for most houses. Architectural asphalt shingles run about $5.50 to $8.50 per square foot of roof surface; standing-seam metal runs $11 to $22. The spread is driven by roof area, pitch and material, not by the floor area of your house.
Because roofers price the roof surface, not your floor plan. A 1,500 square foot bungalow has considerably more than 1,500 square feet of roof once pitch, overhangs and dormers are counted. Ask every quote for the roof area in squares, then the price per square.
One hundred square feet of roof surface. It is the unit the trade actually quotes in, and knowing it is the fastest way to compare two bids that look nothing alike. A typical detached house roof is somewhere between 18 and 30 squares.
A full tear-off is the safer job and is what most reputable quotes assume. Laying over saves money now, hides whatever is wrong with the decking, and can void manufacturer warranties. Ontario roofs also carry snow load, which argues against extra weight.
Architectural asphalt shingles are generally expected to last around 25 to 30 years, though freeze-thaw cycles, ice damming and poor attic ventilation shorten that considerably. Metal roofing is quoted at 40 to 70 years, which is much of what the higher price buys.
Almost always rotten decking found after the tear-off, which nobody can see until the old roof is off. A good quote states the price per sheet of replacement plywood in advance. A quote that is silent on it is a quote with an open end.
Late spring through early autumn. Shingles need warmth to seal properly, so work done in deep cold may not bond until the following spring. Crews are busiest from June to September, and booking in the shoulder months usually means better attention.
Sources
Price ranges are drawn from published 2026 cost guides of Ontario and GTA roofing companies, checked on 17 September 2026. These are published by firms that sell roofing, and are quoted here as market pricing rather than independent data; confirm with written quotes for your own roof. Material lifespans are manufacturer and trade expectations, not guarantees — Ontario freeze-thaw cycles and attic ventilation affect them substantially. Ontario24 is a classified directory and does not perform, inspect or warrant roofing work.