When a commercial roofing project lands on your desk — whether it’s a full replacement, a nagging leak that keeps coming back, or a maintenance program you’ve been putting off — the first real decision you face is who to hire. And that decision carries weight well beyond the project itself, because the commercial roofing contractor you choose will affect how your roof performs for the next 20 to 30 years.
Most property owners start by collecting bids and comparing the bottom line. That’s a reasonable place to begin, but the bid alone doesn’t tell you much about the contractor behind it. What tells you more is the conversation you have before the bid — the questions you ask, and how the contractor answers them.
Some of these questions are straightforward. Others are the kind that separate experienced, trustworthy commercial roofing contractors from the ones who look good on paper but create headaches down the road. Here’s what to ask and what to listen for.
Licensing and Qualifications
Before you get into scope and pricing, confirm that the contractor is actually qualified to do commercial roofing work in your state. This sounds basic, but licensing requirements vary quite a bit depending on where your building sits.
“Are you licensed for commercial roofing in this state?”
Arizona, for example, requires a specialty classification through the Registrar of Contractors, with separate licenses for residential and commercial projects. California requires a C-39 Roofing Contractor License through the Contractors State License Board. Utah mandates a specialty contractor license through the Division of Professional Licensing, and Idaho requires registration with the state’s Contractors Board. Colorado doesn’t have a state-level requirement for roofing contractors, but licensing residing at a city level — Denver being the most notable — have their own commercial licensing requirements. Oregon and Washington each maintain their own registration and licensing structures too.
A licensed commercial roofer should hand over their license number without hesitating. If the response is vague or you get a runaround, pay attention to that.
“What manufacturer certifications do you hold?”
The certifications a contractor holds directly affect what warranty coverage is available on your project. Major manufacturers each run their own certification programs. Contractors who complete those programs can offer the manufacturer’s fuller warranty packages, including NDL (No Dollar Limit) warranties that cover the entire roofing system without a cap on repair or replacement costs.
Without the right certification, you may be limited to a basic material-only warranty, which is a fundamentally different level of protection. On a large commercial building, that gap in coverage can easily be worth tens of thousands of dollars.
“Can you show me projects similar to mine?”
Commercial roofing spans everything from strip malls to hospitals to warehouses, and the skills involved don’t all transfer neatly from one building type to the next. A contractor experienced in warehouse re‑roofing may lack the coordination, safety planning, and tenant‑management expertise required for occupied office buildings or school campuses.
Ask for relevant examples and references you can actually call — a professional roofing contractor with the right experience will be happy to share them.
The Estimate and Scope of Work
Once you’re confident in the contractor’s qualifications, the next layer of questions focuses on what they’re actually proposing.
“Can you walk me through this estimate line by line?”
A solid estimate from a commercial roofing company should separate materials, labor, timeline, and warranty terms clearly enough that you can compare it directly against another contractor’s proposal. You should be able to see exactly what roofing system is being recommended, what thickness and grade of membrane is specified, how many days or weeks the project will take, and what the warranty covers.
Lump-sum bids that bundle everything together make it nearly impossible to compare roofing estimates and warranties across contractors. They also make it harder to evaluate change orders if something unexpected comes up mid-project.
“What system are you recommending, and why this one for my building?”
The answer should connect back to your building’s specific conditions — its age, the current state of the existing roof, how the building is used, what challenges you’re dealing with, and what your budget allows. A thoughtful commercial roofing contractor will evaluate the roof in front of them and recommend a system based on what the particular project calls for.
A contractor who gives the same recommendation for every roof isn’t evaluating your particular property — they’re instead selling their preferred product.
“How do you handle unexpected conditions once the project starts?”
On commercial roofing projects, it’s common to find hidden moisture, damaged insulation, or deck problems that weren’t visible before the existing roof came off. What matters is how the contractor handles that discovery: is there a documented process for scoping additional work, getting your approval, and adjusting the price? Or do you find out about it on the invoice?
Transparency here is a strong indicator of what the working relationship will actually feel like.
Warranty Terms
Warranty terms are one of the most consequential (and routinely misunderstood) parts of a commercial roofing project. A good commercial roofing contractor should be able to clearly explain the two main types of warranty coverage, how they differ, and what you need to do to keep them in effect.
“What does the warranty cover — materials, labor, or both? And for how long?”
Warranty options range from basic material-only coverage to full-system NDL (No Dollar Limit) warranties that cover the entire roofing assembly without a cap on repair or replacement costs. The level of coverage available on your project can depend on several factors, including the roofing system selected and the installing contractor’s certification status with the manufacturer. Ask your contractor how their certification level affects the warranty options available to you. .
Workmanship warranties — covering the quality of the installation itself — vary from contractor to contractor. The NRCA notes that there’s no industry standard for workmanship warranty duration. Some contractors offer a year or two, while others offer longer terms. Get the specifics in writing, including what’s covered, what’s excluded, and what conditions apply.
“What would void the warranty?”
Warranty exclusions vary by manufacturer and by contract. Common areas to ask about include inspection and roof maintenance requirements, what happens if other trades do work on the roof, and how modifications or unreported damage might affect coverage.
Getting clear answers here before the project starts helps you avoid surprises later. Your contractor should be willing to review these details with you so you know exactly what’s required to keep your coverage intact.
“Is the warranty transferable if I sell the property?”
If there’s any chance you’ll sell the building within the warranty period, ask whether the manufacturer warranty transfers to a new owner and whether there are any fees or conditions involved. Not all warranties work the same way on this front, and the answer can affect your property’s value at resale.
Project Execution and Logistics
The logistics of a commercial roofing project affect your tenants, your daily operations, and your liability. These questions help you understand what the weeks or months of active work will look like from inside the building, not just on top of it.
“Who is my point of contact, and how will you communicate progress?”
You want a dedicated project manager who knows the job, knows your building, and picks up the phone when you call — not a different crew lead every time you have a question. Ask how often you’ll get updates and in what format. Commercial roofing projects involve many moving parts. Clear, consistent communication is necessary to avoid delays and disputes.
“How will you minimize disruption to tenants and building operations?”
If your building is occupied — such as an office, retail space, healthcare facility, school, or apartment community — this is a critical consideration. The answer should be tailored to your situation, covering work hours, noise management, debris handling, signage, restricted access areas, and coordination with your property management team.
“What does your safety program look like?”
Commercial roofing involves fall hazards, heavy materials, and work happening above people’s heads. OSHA has specific requirements for the industry, and this is an area where you want concrete answers rather than general assurances. Ask about their safety program, how they meet OSHA requirements for commercial roofing work.
After the Project Wraps
A roofing project might last a few weeks, but the roof itself needs to hold up for two decades or more. Understanding the contractor’s long-term involvement helps you judge whether they see the relationship the same way you do.
“Do you offer inspection or maintenance programs?”
Most manufacturer warranties require annual inspections to remain valid, and having the contractor who installed your roof handle that maintenance creates useful continuity — they already know the system, the building, and the history. It also means there’s no question about whether the roof maintenance program meets the warranty’s documentation standards.
“How do I reach you if there’s a problem down the road?”
Find out if they have a service team that handles warranty calls and what their typical response time looks like. Commercial roofing services don’t end after installation — ongoing support and contractor accessibility years after the project are just as critical as the initial workmanship.
After the Project Wraps
A roofing project might last a few weeks, but the roof itself needs to hold up for two decades or more. Understanding the contractor’s long-term involvement helps you judge whether they see the relationship the same way you do.
“Do you offer inspection or maintenance programs?”
Most manufacturer warranties require annual inspections to remain valid, and having the contractor who installed your roof handle that maintenance creates useful continuity — they already know the system, the building, and the history. It also means there’s no question about whether the maintenance meets the warranty’s documentation standards.
“How do I reach you if there’s a problem down the road?”
Find out if they have a service team that handles warranty calls and what their typical response time looks like. Commercial roofing services don’t end after installation — ongoing support and contractor accessibility years after the project are just as critical as the initial workmanship.
Making the Decision
Hiring a commercial roofing contractor is one of the bigger decisions you’ll make as a property owner or manager, and it’s one where doing your homework upfront pays off for years afterward. The right questions lead to better information, and better information leads to a hire you won’t second-guess when the first heavy rainstorm hits.
Highland Commercial Roofing works with commercial property owners and managers across the Western United States to plan and execute roofing projects — from targeted repairs to full replacements to long-term maintenance programs.
If you’ve got a project on the horizon and want to talk through what it involves, give us a call at (866) 880-5252 or email info@highlandroof.com.
Frequently Asked Questions About Choosing a Commercial Roofing Contractor
Ask about certifications from the manufacturers whose roofing system is being proposed. The most common in commercial roofing include GAF, Carlisle, Versico, and Johns Manville. Each runs its own training and certification program, and the contractor’s certification level can affect what warranty options are available on your project. It’s also worth confirming that the contractor carries current state licensing, liability insurance, and workers’ compensation coverage.
Look at what’s included, not just the total. A well-prepared estimate separates material costs, labor, project timeline, and warranty terms so you can compare apples to apples. Pay attention to whether each contractor is specifying the same roofing system and material grade — a lower price often reflects a different scope, not a better deal. If an estimate is a single lump-sum number without detail, ask for a breakdown before making any comparisons.
Generally, these two warranties cover different issues. A manufacturer warranty addresses defects in the roofing materials, while a workmanship warranty covers the contractor’s installation. They operate independently, so it’s worth asking your contractor to explain how each one applies to your specific project — including what’s covered, for how long, and what could void the coverage.
It depends on what’s being done and how big the building is. A targeted repair might wrap up in a few days, while a full roof replacement on a large commercial property could take several weeks. Weather, material lead times, and building-specific logistics — like restricted work hours on occupied properties or coordination with tenants — all affect the schedule. Your contractor should provide a realistic timeline as part of their proposal.
Both can do good work, but the strengths tend to differ. Regional contractors usually have deeper knowledge of local building codes, the permitting process, and climate-specific material performance in their market. They’re often faster to respond on warranty or service calls, and they carry a direct reputational stake in the communities they serve. National firms may bring broader resources and capacity for very large projects. The right choice depends on the size and complexity of your project, your building’s location, and how much you value an ongoing local relationship with your roofing partner.
About Highland
Highland Roofing Company is a regional roofing provider, with offices strategically located across California, Arizona, Nevada, Utah, Colorado, Oregon and Washington. Over the past 30+ years, our commercial roofing contractors have proven just how powerful that approach can be. It’s the reason why we’ve been able to grow from a small local contractor into one of the leading commercial roofing companies in the West while maintaining the same level of outstanding commercial roofing service every step of the way.
