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Straight answers
The questions people ask most about starting and running a commercial roofing business in Ontario. Answered straight, with links to the official sources.
Almost everything changes: membrane systems (TPO, EPDM, mod-bit) instead of shingles, property managers and owners instead of homeowners, tenders and service contracts instead of door-knocking, manufacturer-certified warranties instead of workmanship promises, and crews trained on torch and heat-weld instead of nail guns. The barrier to entry is much higher (certification, torch-safety, bigger insurance) — and so is the ceiling, with recurring inspection-and-repair contract revenue that residential roofing doesn't have.
The major manufacturers (Carlisle, Soprema, Firestone, IKO Commercial, Sika Sarnafil) certify contractors through training, supervised installations, and ongoing quality audits — because their system warranty rides on your workmanship. Certification is the ticket to specified commercial work; without it you're limited to repairs and uncertified jobs. Your path to running work is becoming the certified foreman or contractor the manufacturer's warranty depends on.
Serious enough that it defines the whole safety culture. Torch-applied (mod-bit) roofing uses open flame on a building, and a membrane fire can destroy the building and end your company — insurers scrutinize hot-work procedures closely. High CGL limits, strict hot-work permits, mandatory fire-watch after torching, and rigorous crew discipline are non-negotiable. The fire exposure is the single biggest risk in commercial roofing, and managing it is a core part of running the business (and staying insurable).
Roof-maintenance programs: scheduled inspections, drain clearing, seam checks, and minor repairs sold as annual contracts to property managers. Warranties often require documented maintenance, which makes the contract an easy sell — and the contractor doing the maintenance is first in line when the roof needs replacing. That recurring inspection-and-repair revenue, plus the replacement pipeline it creates, makes commercial roofing far more stable than one-off residential work.
For people willing to clear it, yes. The certification, torch-safety, and insurance requirements keep out the casual competition that floods residential roofing, so the market is less crowded. Combine that with higher-value projects, manufacturer-warranty work, and recurring service contracts, and the ceiling ($120k–200k+ for owners) and stability beat residential. The trade-off is the investment in certification, safety systems, and the harder-to-acquire skills — but that barrier is exactly what protects the margins.
Build membrane-system and torch/heat-weld skills on flat-roof crews, earn manufacturer certification (the gate to warrantied work), and put serious safety and hot-work systems in place. Carry high CGL limits, register WSIB (roofing is a high rate group), and keep Working at Heights current across the crew. Anchor on service and maintenance contracts for recurring revenue, and use them as the pipeline to replacement work. It's a higher-barrier start than residential, but a more durable business.
Almost everything changes: membrane systems instead of shingles, property managers and owners instead of homeowners, tenders and service contracts instead of door-knocking, manufacturer-certified warranties instead of workmanship promises, and crews trained on torch/heat-weld instead of nail guns. Higher barrier to entry, much higher ceiling, and revenue that recurs through inspection and repair contracts.
The major manufacturers (Carlisle, Soprema, Firestone, IKO Commercial, Sika Sarnafil) certify contractors through training, supervised installs, and ongoing quality audits — because their system warranty rides on your workmanship. Certification is the ticket to specified commercial work; without it you are limited to repairs and uncertified jobs.
Roof-maintenance programs: scheduled inspections, drain clearing, seam checks, and minor repairs sold as annual contracts to property managers. Warranties often require documented maintenance, which makes the contract an easy sell — and the contractor doing maintenance is first in line when the roof is replaced.
A sole proprietorship is cheaper and simpler to start, but you are personally liable for the business's debts and claims. Incorporating creates a separate legal entity that limits personal liability, can reduce tax once you are profitable, and reads as more credible to larger clients. Most contractors incorporate once they have employees, real revenue, or work on others' property.
Yes — construction is a mandatory WSIB sector in Ontario. Even independent operators and partners with no employees generally must register, and clients and general contractors will require a valid WSIB clearance certificate before you can work on their site.
You must register for and charge HST once your revenue exceeds $30,000 over four consecutive quarters. Many contractors register before that threshold so they can claim input tax credits on tools, materials, and vehicles from day one.
Ontario's Construction Act sets the rules: a 10% holdback on most contracts, prompt-payment timelines (you must be paid within set periods after a proper invoice), and an adjudication process for disputes. Understanding holdback, lien rights, and prompt payment is essential to protecting your cash flow.