A roofer who has spent ten years on residential reroofs and then wins a strip-mall membrane job has not just changed the work. They have changed what their insurance is rating. Commercial roofing brings different heights, different materials, different contract terms and a different claims profile, and carriers price all four. The contractors who get caught out are not the ones who take commercial work — they are the ones who take it without telling anybody, and discover the consequences at audit or at claim.
1. The Split of Operations Is the Number That Prices You
Applications ask for a percentage split between residential and commercial work, and between new construction and existing or remodel. Contractors treat these as administrative questions and answer them from memory. Underwriters treat them as the rating basis, because a roofer who is ninety percent residential reroof is a different risk from one who is half new-construction commercial.
The answer matters more than the total revenue. Two contractors with identical sales and identical payroll can be quoted differently on the strength of that split alone, because it drives which carriers will write the account at all. Roofing programmes are narrow: many are built for one profile and will decline the other.
Answer it from your records, not your impression, and update it when it moves. A split that was accurate at inception and is wrong by renewal is the kind of discrepancy that surfaces during a claim investigation, at the least convenient moment.
2. Height, Access and What They Do to Workers' Comp
Residential steep-slope work is dangerous in a familiar way. Commercial work introduces height, roof-edge exposure over occupied space, mechanical plant, and often crane or hoist use for materials. The severity profile of a fall changes with height, and workers' compensation is severity-driven.
Some roofing programmes carry explicit height or storey restrictions as endorsements. It is entirely possible to hold a policy that simply does not cover work above a stated height, and to discover it after a loss. If commercial is a direction you are moving in, that endorsement list is the first thing to check.
Access changes your general liability exposure too. Working over an occupied retail unit or a live car park puts third parties directly beneath your work all day, which is a different public-liability picture from a suburban street.
3. Materials and Hot Work
Low-slope commercial roofing means membranes: TPO, EPDM, modified bitumen, and in some cases torch-applied systems. Torch-down work is a fire exposure, and carriers treat it as one. Expect questions about what percentage of your work involves open flame, and expect a hot-work warranty if the answer is anything but zero.
A hot-work warranty is a condition of coverage, not a suggestion. It typically requires a fire watch for a set period after the torch is shut down, along with documented procedures. Failing to meet the warranty on the day of a fire is one of the cleanest coverage denials in the trade.
Even without open flame, the equipment changes. Kettles, hot-air welders and adhesives all shift your tools and equipment exposure, and your inland marine schedule should follow the equipment rather than lag a year behind it.
4. The Contract Terms Are Harder, and They Reach Your Policy
Commercial customers issue their own contracts. Those contracts routinely require higher general liability limits, an umbrella, additional insured status on a primary and non-contributory basis, a waiver of subrogation, and completed-operations coverage running for a defined number of years after the work.
Each of those is an insurance instruction, and every one of them has a cost or a form behind it. Agreeing to indemnify a property owner broadly, then finding your policy will not respond to the liability you assumed, is a contractual exposure you created with a signature rather than a ladder.
The practical sequence is to send the insurance requirements section of any commercial contract to your broker before you sign, not after you win. The answer to whether your programme can meet them takes minutes; restructuring a programme mid-term to meet them takes longer and costs more.
5. The Claims Profile Is Different in Shape, Not Just Size
Residential claims tend to be frequent and moderate: interior water damage, a broken window, a damaged driveway. Commercial claims are less frequent and much larger, because what sits under a commercial roof is inventory, tenants, and business income.
That severity is why commercial-capable programmes push you toward higher limits and an umbrella. A single membrane failure over a tenant's stock can exhaust a limit that would have been ample for a decade of residential work.
It also changes how long claims stay open. Commercial construction-defect allegations take years to resolve, which is where completed-operations duration and whether defence costs erode your limit stop being fine print and start being the whole question.
6. Bonding, Prequalification and the Paperwork Wall
Commercial and public work introduces a requirement most residential roofers have never met: bonds. Bid bonds, performance bonds and payment bonds are not insurance — they are a credit product, underwritten against your balance sheet, your work-in-progress schedule and your track record on jobs of similar size. A surety is asking whether you can finish, not whether you might cause damage.
That distinction surprises contractors who assume their insurance broker can produce a bond as quickly as a certificate. Surety underwriting wants reviewed or audited financial statements, an ageing schedule, and evidence you have completed jobs of comparable value. Building that file takes months, which is why the time to start is before the first bonded job appears, not the week it is due.
Prequalification packets ask the same questions in a different order: experience modification factor, OSHA incident rates, loss runs for three to five years, and named safety personnel. A clean experience mod stops being an insurance metric at that point and becomes a sales asset — it is often the number that decides whether you are allowed to bid at all.
7. What Actually Changes on the Ground
The operational differences show up before the insurance ones do. Commercial sites run to schedules set by other trades, with site inductions, permits to work, and rules about when noisy or hot work may happen. Deliveries are craned rather than carried. There is usually a general contractor whose own insurer has opinions about your fall-protection plan.
All of that is manageable, and most roofers who make the move find the work steadier and the margins more predictable than storm-driven residential. The failure mode is rarely capability. It is cash flow and paperwork: retainage held for months, pay-when-paid clauses, and a documentation burden that a two-person office was not built for.
Treat the first commercial job as an operational pilot rather than simply a bigger version of what you already do. Price the administrative time into the bid, and be candid with your broker about how much of it you intend to take on, because a programme built for occasional commercial work is priced differently from one built for a contractor moving there permanently.
8. What to Tell Your Broker, and When
Before you bid: the type of building, the height, the roof system, whether hot work is involved, whether you will subcontract any of it, and the insurance requirements in the customer's contract. That is a five-minute conversation that determines whether you are quoting a job you can actually insure.
At renewal: the real split of operations for the year just finished and your honest estimate for the year ahead. Estimating your commercial percentage low to hold the premium down produces the same audit outcome as understating payroll — a bill later, with less goodwill.
The direction of travel matters as much as the snapshot. A contractor who tells their broker they intend to move from ten percent commercial to forty over two years gets a programme built for where they are going. One who does it quietly gets re-rated after the fact.
This article is general information for roofing contractors, not legal or coverage advice. Policy wording, statutes and rating rules vary by carrier and by state — read your own forms and talk through your programme with a broker who writes roofing. Get a quote.