Size is footprint × pitch, not floor area
Start with the ground-floor footprint the roof actually covers, multiply by the pitch factor, then add waste. A two-storey’s floor area is not its roof area — the calculator handles this for you.
Price your roof
Adjust any field600 sq ft4,000 sq ft
Pitch factors from Ontario contractor guides.
Installed rates incl. tear-off, labour, underlayment, standard flashing.
NorthPeak estimate: complexity labour allowance.
Ontario code allows max two shingle layers.
GTA premium per Ontario contractor guides.
The video
As featured in our True Cost series
This calculator is the companion to Episode 2 of the NorthPeak True Cost series — the one about what the roofing quote doesn’t tell you.
“The REAL cost of a new roof in Ontario? Between eight and twenty thousand dollars — here’s what the quote doesn’t tell you.” — Episode 2 hook, NorthPeak True Cost
- Hidden cost one — rot: when old shingles come off, damaged decking gets billed extra — on top of the quote. Usually $3–$6 per square foot replaced.
- Hidden cost two — HST: 13% in Ontario, and plenty of quotes don’t include it. Toggle it above and watch.
- Hidden cost three — where you live: GTA jobs run 15–25% above smaller Ontario markets.
How to read your roofing quote
Material is the biggest lever
Architectural asphalt ($4.50–$8.00/sq ft) is the common value choice. Metal ($12–$22) costs roughly double but can last 40–70 years; cedar ($10–$18) is premium heritage material. All installed rates above include tear-off, labour, underlayment and standard flashing.
Decking: get the unit price in writing
Because rot is unknowable before tear-off, a good contract names a per-sheet or per-square-foot allowance and requires your approval before the crew exceeds it. The calculator’s allowance (10% of area at $3–$6/sq ft) is an estimate for planning.
Compare three identical scopes
Give every roofer the same material, tear-off, flashing, ventilation, decking allowance, permit and warranty scope. Compare exclusions as carefully as totals — a low quote may omit tear-off, flashing or disposal. Verify liability insurance and WSIB clearance.
Free checklist
Get the True Cost roofing checklist by email
A one-page printable checklist: the quote line-items that matter, the three hidden costs from Episode 2, and the questions that expose a thin quote — free.
- Every line a roofing quote should show
- The 3 hidden costs from Episode 2
- Questions to ask before signing
Your name and email are sent to northpeakestimates@proton.me via FormSubmit so we can deliver the checklist. We never sell your information.
New roof cost FAQ
How much does a new roof cost in Ontario in 2026?
A typical full architectural-asphalt replacement runs about $8,000–$20,000, at $4.50–$8.00 per square foot installed. Larger, steeper or more complex roofs cost more; metal and cedar cost substantially more per square foot.
Does a roofing quote include HST in Ontario?
Not always — many quotes exclude it. Ontario HST is 13% (CRA), so always ask whether the displayed total is before or after tax. The calculator lets you toggle it.
How much does a tear-off cost versus an overlay?
Our planning model treats $1–$2.50 per square foot as the tear-off and disposal portion of the job. An overlay skips that portion but can hide decking problems — confirm code, existing layers and warranty terms first.
How much more does a roof cost in the GTA?
GTA labour, parking and logistics can place a comparable roof about 15–25% above smaller Ontario markets, per Ontario contractor guides. The calculator uses +20% as the midpoint.
What are hidden decking costs?
Once old shingles come off, damaged plywood or OSB decking commonly bills at $3–$6 per square foot replaced. You won’t know until tear-off, so ask for a per-sheet or per-square-foot allowance in writing.
How many roofing quotes should I get?
Get at least three written quotes on the same scope. Compare exclusions, warranties, insurance and unit prices for hidden repairs — not just the bottom line.
Sources & method
Pricing checked October 2026. Ranges are rounded planning estimates, not quotes.
- Custom Contracting — New Roof Cost Ontario 2026 (asphalt $4.50–$7.00, premium $6–$9, metal $12–$22, cedar $10–$18 per sq ft; GTA +15–25%; decking $3–$6/sq ft; double tear-off $1,000–$2,500).
- Custom Contracting — Roofing Cost Ontario 2026 (per-square-foot installed rates incl. tear-off, labour, underlayment, flashing; pitch factors).
- Canada Revenue Agency — GST/HST calculator and rates (Ontario HST 13%).
- NorthPeak — How Much Does a New Roof Cost in Ontario? (2026) (planning ranges, tear-off $1–$2.50/sq ft, quote-comparison guidance).
The calculator multiplies footprint × pitch factor to get roof surface, applies the material’s installed rate (which includes tear-off, labour, underlayment and standard flashing), then applies complexity and regional factors. Overlay subtracts $1–$2.50/sq ft; two-layer removal adds a flat $1,000–$2,500. Decking allowance (10% of area at $3–$6/sq ft), permits ($250–$750) and 13% HST are optional line items. It is an editorial planning model, not a quote or survey result.