Roof Replacement Cost in the GTA: Shingles vs Metal vs Flat (2026)

What a GTA roof replacement actually costs in 2026

Roofing quotes swing wildly across the GTA because homeowners are often comparing apples to oranges - one number includes a full tear-off to bare decking with new ice and water shield, and the other is a cheaper overlay that skips half the work. Before you compare two quotes, make sure they cover the same scope. Below are real 2026 ranges for the three roofing systems we install most often in Toronto, Mississauga, Brampton and Vaughan.

Typical Toronto, Mississauga and Vaughan house sizes and what they cost

Housing stock varies enough across the GTA that a single per-square-foot number is not that useful on its own. Toronto's older semis and bungalows in Scarborough and Etobicoke tend to have simple gable roofs under 2,000 sq ft of surface. Mississauga and Brampton's 1990s-2000s two-storey subdivisions run larger, often 2,400-3,200 sq ft with more hips and valleys. Vaughan and Richmond Hill's newer executive homes frequently exceed 3,500 sq ft of roof surface with multiple roof planes, turrets and dormers that add labour independent of material cost.

Tear-off vs overlay: why one costs more and lasts twice as long

An overlay means nailing new shingles directly over the existing layer. It is cheaper up front - typically $1.50-$2.50 per sq ft less than a tear-off - because there is no disposal and less labour. It is also, in almost every case, the wrong call on a GTA home. The Ontario Building Code allows a maximum of two layers of asphalt shingles on most residential roofs, so if your home already has one layer, an overlay uses up your last option and hides the deck from inspection.

A tear-off strips the roof to bare decking, lets the crew inspect and replace rotted sheathing, and allows a full, code-compliant ice and water shield installation instead of relying on whatever underlayment is already there. Every reputable GTA roofer will tell you the same thing: overlays trap heat, void most manufacturer warranties, and typically fail 5-10 years earlier than a proper tear-off and reroof.

Decking replacement: the line item that changes everything

Roof decking (sheathing) in GTA homes built before the 1990s is often 1x6 board decking rather than plywood or OSB sheets, and it hides rot at nail lines and around old vent penetrations that nobody sees until the old shingles come off. Expect the crew to flag some amount of decking replacement on almost any tear-off over 20 years old.

Ice and water shield: an Ontario-specific requirement, not an upsell

GTA winters produce ice damming - snow melts from attic heat loss, refreezes at the cold overhang, and backs water up under shingles. The Ontario Building Code addresses this directly by requiring a self-adhering ice and water membrane along eaves, extending from the edge of the roof to at least 900 mm up-slope past the interior face of the exterior wall. On a shallow-pitch roof or one with a wide overhang, that distance up-slope can be considerably more than 900 mm measured along the roof surface.

• Full eave coverage per OBC minimum, priced into every legitimate GTA quote.
• Valleys - the single highest-volume water path on any multi-plane roof, always fully membraned.
• Around chimneys, skylights and all roof penetrations, extending at least 300 mm beyond the flashing on each side.
• Low-slope sections under 4:12 pitch, which often get full-surface ice and water shield rather than just the eave strip.

Attic ventilation: the part most homeowners never see

A roof is only as good as the attic underneath it. Ridge vents, soffit intake vents and baffles work together to keep the underside of the deck cold in winter (reducing ice damming) and to exhaust heat and moisture in summer (extending shingle life). Most manufacturer warranties on architectural shingles explicitly require balanced intake and exhaust ventilation to remain valid, and a roofer replacing shingles without checking the attic's net free ventilation area is setting the new roof up to underperform its rating.

Adding or upgrading ridge venting during a reroof typically costs $8-$14 per linear foot, and clearing or adding soffit intake vents runs $150-$450 depending on how many bays need baffles installed. On a home with visible attic frost or ice damming history, this is not optional work - it is the fix.

Warranty types: material, workmanship and what actually protects you

Roofing warranties come in layers that homeowners often assume are one thing. Reading the fine print before signing matters more than the headline number on the brochure.

Permit rules across the GTA

Most GTA municipalities, including Toronto, Mississauga, Brampton and Vaughan, do not require a permit for a like-for-like reroof (same footprint, same roof lines, no structural change). A permit is generally required when the scope includes structural repair, a change in roof shape or pitch, converting a flat roof to a sloped one, or adding a dormer or skylight that alters framing. A licensed roofer pulls the permit themselves as part of the job when it is needed and includes the fee in the quote.

Seasonal pricing across the GTA roofing calendar

Roofing is seasonal work, and pricing moves with demand. Spring and early summer (May-June) tend to have the most competitive pricing and best availability because crews are ramping up after winter and before the fall rush. September and October are the busiest months in the GTA - everyone wants a new roof before winter - and booking windows stretch to 6-10 weeks with less room to negotiate. Winter installs are possible but limited to milder days, cost more due to slower material handling and heated storage, and are usually reserved for emergency leak repairs rather than full replacements.

Comparing quotes: a side-by-side worksheet

The single biggest mistake GTA homeowners make is comparing the bottom-line number on three quotes without checking whether they include the same scope. Use a table like this to line up what you actually received.

Getting a firm number for your home

An accurate roofing quote requires an on-site measurement, not a satellite estimate. Roof pitch, number of layers, decking condition and ventilation all change the final number, and a technician needs to walk the roof and the attic to confirm them. Book an on-site assessment before your existing roof starts leaking, since emergency replacements in the GTA cost more and leave less room to choose material or scheduling.