Southwestern Ontario · Q3 2026
Roof renovation cost in London and southwestern Ontario
Tear-off layers, sheathing repair, and complexity. The figures below are modelled for Southwestern Ontario using our 0.98× regional cost multiplier, on a detached home built 1960-1989 at a mid-range finish.
Typical planning budget
$11,800 to $19,050
Typical $14,250 · includes 17% contingency
Before contingency
Why London and southwestern Ontario differs
London and southwestern Ontario prices about 2% below Ottawa, which is the baseline our regional model is anchored to.
- Regional multiplier
- 0.98×
- Versus Ottawa
- -2%
- Province
- Ontario
- Sales tax on services
- HST (13%)
Regional multipliers are anchored to Ottawa at 1.00 and scaled using Statistics Canada's Residential Renovation Price Index and Building Construction Price Index movements by census metropolitan area, then cross-checked against published contractor rate ranges. They are planning-level adjustments, not surveyed local quotes.
Areas this covers
Southwestern Ontario is modelled as a single labour market, so these municipalities share the same cost multiplier:
- London
- Windsor
- Kitchener
- Waterloo
- Guelph
- Cambridge
Somewhere else in Ontario? Compare every Ontario region.
Cost by finish level in London and southwestern Ontario
Finish level moves the number more than almost anything else you control. All three rows use the same London and southwestern Ontario multiplier and the same scope.
| Finish | Low | Typical | High |
|---|---|---|---|
| BudgetStock materials, simple details, value fixtures | $8,900 | $10,800 | $14,400 |
| Mid-rangeCommon homeowner choice: durable materials, better fixtures | $11,800 | $14,250 | $19,050 |
| PremiumHigh-end materials, custom detailing, designer fixtures | $16,550 | $20,000 | $26,700 |
Cost by size in London and southwestern Ontario
Typical all-in planning budgets at three representative sizes, mid-range finish.
| Size | Low | Typical | High |
|---|---|---|---|
| 1,200 sq ft | $8,550 | $10,350 | $13,850 |
| 1,800 sq ft | $11,800 | $14,250 | $19,050 |
| 2,600 sq ft | $16,100 | $19,400 | $25,950 |
Where the money goes
The $14,250 typical figure for London and southwestern Ontario, broken into the lines a contractor quote should also separate.
| Category | Low | Typical | High |
|---|---|---|---|
| Materials | $3,950 | $4,750 | $6,350 |
| Labour | $3,950 | $4,750 | $6,400 |
| Demolition and disposal | $1,550 | $1,900 | $2,500 |
| Permit and design allowance | $650 | $800 | $1,050 |
| Subtotal | $10,100 | $12,200 | $16,300 |
| Contingency (17%) | $1,700 | $2,050 | $2,750 |
| Total planning budget | $11,800 | $14,250 | $19,050 |
Compared with the rest of Ontario
Same project, same scope and finish, priced against every other Ontario region we model.
| Region | Multiplier | Typical | vs London and southwestern Ontario |
|---|---|---|---|
| London and southwestern Ontario (this page) | 0.98× | $14,250 | — |
| Toronto | 1.15× | $16,650 | +17% |
| GTA (outside Toronto) | 1.10× | $15,950 | +12% |
| Hamilton and Niagara | 1.05× | $15,200 | +7% |
| Ottawa | 1.00× | $14,500 | +2% |
| Northern Ontario | 0.97× | $14,100 | -1% |
| Other Ontario | 0.95× | $13,750 | -4% |
Permits in Ontario
Building permits are issued by your municipality under the Ontario Building Code. Requirements and fees differ from one city to the next.
Commonly triggered by this project
- Roof structure or sheathing changes. Replacing shingles is often exempt, but structural repairs, added skylights, or new sheathing layers can require a permit.
Hiring in Ontario
Ontario does not license general contractors or renovators. Anyone can advertise renovation work, so the paperwork you check matters more than any claimed credential.
Trades that must be certified
- Electrical: Only a licensed electrical contractor may do electrical work for hire. The licence number starts with ECRA/ESA and is searchable.
- Gas and propane: Gas lines, furnaces, fireplaces, and water heaters must be handled by a TSSA-certified gas technician.
- Plumbing: Plumbing is a compulsory trade in Ontario. Ask for a Certificate of Qualification from Skilled Trades Ontario.
- New homes and substantial additions: Building or selling a new home in Ontario requires an HCRA licence. Ordinary renovations do not.
Costs people forget on this project
Included as allowances above. Check any quote covers them too.
- Plywood replacement discovered during tear-off
- Ice and water shield coverage requirements
- Chimney, vent, and wall flashing
- Attic ventilation corrections
- Multiple disposal bins for layered roofs
- Access equipment for steep or tall roofs
Typical schedule: 1 to 4 days for a typical asphalt reroof.
Questions homeowners ask
- Can I put new shingles over old ones?
- Sometimes, but an overlay hides sheathing problems, adds weight, and usually shortens the life of the new roof. Most quotes assume a full tear-off for good reason.
- Why do quotes include a plywood allowance?
- Damaged sheathing only becomes visible after tear-off. A per-sheet or per-square-foot allowance keeps that repair from becoming an open-ended change order.