The Contractor Matters More Than the Material
Here's a truth most building owners learn the hard way: the quality of your roofing contractor matters more than the roofing system you choose. A skilled contractor can make any quality material perform well. A poor contractor can ruin the best materials on the market.
Commercial roofing is specialized work. The contractor who did your neighbor's shingle roof isn't qualified to install a TPO membrane system. And the lowest bidder often costs you more in the long run.
This guide helps you find a contractor you can trust with one of your building's most critical systems.
Start with the Right Pool of Candidates
Before evaluating contractors, make sure you're looking at the right ones.
Commercial Experience Is Non-Negotiable
Commercial flat roofing is fundamentally different from residential work:
- •Different materials and installation techniques
- •Different drainage requirements
- •Different structural considerations
- •Different code requirements
- •Different warranty structures
A residential roofer with 20 years of experience is still unqualified for commercial work. Look specifically for commercial roofing contractors.
Local Matters
Choose contractors based within reasonable distance of your building:
- •They understand local weather challenges
- •They can respond quickly to problems
- •They're familiar with local codes and inspectors
- •Their reputation in your community is verifiable
- •They'll be around for warranty service
A contractor from three states away might offer a lower price, but what happens when you need warranty work?
Where to Find Candidates
Manufacturer referrals: Major membrane manufacturers (GAF, Carlisle, Firestone, Johns Manville) maintain lists of certified installers. These contractors have been trained and vetted.
Industry associations: The National Roofing Contractors Association (NRCA) and regional associations maintain member directories.
Local building owners: Other commercial building owners in your area are excellent sources. Ask who they use and whether they're satisfied.
Online research: Use it to verify, not discover. Check reviews on Google, BBB ratings, and any complaints, but don't rely solely on online presence.
Essential Qualifications to Verify
Once you have a list of candidates, verify these non-negotiable qualifications:
Licensing
Michigan requires roofing contractors to be licensed. Verify:
- •Active license status (check with the state)
- •License covers commercial roofing work
- •License holder is actually the company (not a borrowed license)
Operating without proper licensing is a red flag that suggests the contractor cuts other corners too.
Insurance
Require proof of:
General liability insurance: Minimum $1 million per occurrence, $2 million aggregate. This protects your property if something goes wrong.
Workers' compensation insurance: Covers all employees. Without it, you could be liable if a worker is injured on your property.
Umbrella coverage: For larger projects, additional coverage is wise.
Verify directly with the insurer. Don't just accept a certificate—call the insurance company to confirm the policy is active and covers roofing work at commercial properties.
Bonding
A surety bond provides financial protection if the contractor fails to complete the work or doesn't pay subcontractors. For significant projects, require bonding.
Manufacturer Certifications
The major membrane manufacturers certify contractors who have:
- •Completed installation training
- •Demonstrated proper techniques
- •Met minimum experience requirements
- •Maintained quality standards
Certification matters because:
- •Certified installers can offer manufacturer warranties
- •Training ensures proper installation techniques
- •Certification can be revoked for poor work
Ask which manufacturers have certified the contractor, and verify those certifications directly.
Questions to Ask Every Contractor
During initial conversations and estimates, ask these questions:
About Their Experience
"How long have you been installing commercial roofs?" Look for at least 5-10 years of commercial-specific experience. A company might be old, but recently shifted to commercial work.
"How many roofs like mine have you installed in the past two years?" Recent, relevant experience matters. A contractor who mostly does EPDM might not be the best choice for your TPO project.
"Can you provide references from similar projects?" Ask for 5-10 references, then actually call them. Ask about quality, communication, schedule adherence, and how problems were handled.
"What's your crew's experience level?" Some contractors rely heavily on subcontractors or temporary labor. Experienced, stable crews produce better work.
About Your Project
"Will you inspect my current roof before providing an estimate?" Any contractor who quotes without a thorough inspection is guessing. Accurate estimates require understanding existing conditions.
"What system do you recommend and why?" A good contractor explains options and makes recommendations based on your building, not just what they prefer to install.
"How will you handle drainage?" Drainage problems cause most flat roof failures. The contractor should have a specific plan for ensuring proper drainage.
"What's your plan for weather delays?" Roofing depends on weather. How does the contractor protect partially completed work? What's the policy on schedule changes?
About the Business
"Will you be here in 10 years?" Warranties are worthless if the company disappears. Look for stability: established business, permanent location, long-term employees.
"Who will supervise my project?" You want a specific name and that person's experience level. Large jobs shouldn't be supervised by the newest foreman.
"How do you handle problems?" Every project has unexpected issues. How does the contractor communicate problems and resolve them?
Evaluating Estimates
Getting multiple estimates is standard practice, but comparing them requires attention to detail.
What Should Be Included
A complete estimate specifies:
- •Scope of work: Exactly what's being done
- •Materials: Specific products by manufacturer and type
- •Quantities: Membrane square footage, insulation R-value and thickness
- •Details: How flashings, edges, and penetrations will be handled
- •Drainage: Any modifications to drainage system
- •Removal: What happens to the old roof
- •Timeline: Start date, duration, milestones
- •Payment terms: Schedule and amounts
- •Warranty: Manufacturer warranty terms and contractor workmanship warranty
- •Exclusions: What's specifically not included
Comparing Apples to Apples
Estimates often vary because they're proposing different things:
- •One contractor includes removing the old roof; another plans to overlay
- •One specifies 60-mil TPO; another quotes 45-mil
- •One includes tapered insulation for drainage; another doesn't
- •One offers a 20-year warranty; another offers 10
Before comparing prices, ensure you're comparing equivalent specifications.
The Problem with Lowest Price
The lowest bid isn't always the best value. Low prices often mean:
- •Thinner or lower-quality materials
- •Less experienced crews
- •Shortcuts in details and flashings
- •No budget for doing things right when problems arise
- •Thin margins that put the company at risk
A roof that costs 20% less but fails 10 years early isn't a bargain.
The Problem with Highest Price
The highest price isn't automatically best either. It might mean:
- •Inefficient operations
- •Excessive overhead
- •Simply testing what the market will bear
Price should be evaluated alongside qualifications, not in isolation.
Red Flags to Watch For
Certain behaviors should eliminate a contractor from consideration:
High-pressure tactics: "This price is only good today." Legitimate contractors don't pressure you into quick decisions.
Unusually low bids: If one estimate is dramatically lower than others, something is being left out or corners are being cut.
No physical address: A contractor operating out of a truck or P.O. box may not be around when you need warranty service.
Requesting large deposits: Standard commercial practice is to pay as work progresses, not large amounts upfront.
No written contract: Everything should be documented. Handshake deals provide no protection.
Vague about insurance: Reluctance to provide insurance certificates suggests coverage problems.
Can't provide references: Either they don't have satisfied customers, or they're too new to have a track record.
Disparages all competitors: Professionals focus on their own qualifications, not attacking others.
Won't answer questions: Evasiveness about experience, methods, or terms is always concerning.
The Contract Matters
Before work begins, you need a comprehensive written contract. It should include everything from the estimate plus:
Legal Protections
- •Contractor's license number
- •Insurance policy numbers and coverage amounts
- •Lien waiver provisions
- •Dispute resolution process
- •Termination conditions
Project Specifics
- •Detailed scope of work
- •Specific materials with manufacturer and product names
- •Project schedule with milestones
- •Site access and logistics
- •Protection of existing property
- •Cleanup and debris removal
Payment Terms
- •Total contract amount
- •Payment schedule tied to milestones
- •Retention amount (typically 10% held until completion)
- •Process for change orders
- •What triggers final payment
Warranty Details
- •Manufacturer warranty terms and duration
- •Contractor workmanship warranty duration
- •What's covered and what's excluded
- •Process for making warranty claims
- •Transferability if you sell the building
Have your attorney review significant contracts. The few hundred dollars in legal fees is insurance against much larger problems.
During Construction
Your job doesn't end when the contract is signed.
Stay Engaged
- •Attend the pre-construction meeting
- •Know who to contact with questions
- •Visit the site periodically (with proper safety precautions)
- •Document progress with photos
- •Address concerns immediately, not after the fact
Monitor Quality
- •Are materials as specified?
- •Are seams being welded properly?
- •Are flashings detailed correctly?
- •Is the site being kept clean and safe?
- •Are workers following safety protocols?
Document Everything
- •Keep copies of all correspondence
- •Photograph progress regularly
- •Note any deviations from plans
- •Document weather delays and their handling
- •Record any verbal agreements in writing
Handle Changes Properly
If scope changes are needed:
- •Get change orders in writing
- •Understand cost and schedule impacts
- •Approve before work proceeds
- •Update the contract accordingly
Final Inspection and Closeout
Before making final payment:
Walk the Roof
With the contractor, inspect:
- •Overall membrane appearance
- •Seam quality (especially on TPO/PVC)
- •Flashing details at all penetrations and edges
- •Drainage flow
- •Cleanliness and debris removal
Verify Documentation
Collect:
- •Manufacturer warranty registration
- •Contractor workmanship warranty
- •As-built drawings if applicable
- •Maintenance instructions
- •Lien waivers from all subcontractors and suppliers
Establish Maintenance Relationship
Discuss:
- •Recommended inspection schedule
- •Maintenance the contractor provides
- •How to report problems
- •Emergency contact information
The Long View
A good contractor relationship doesn't end at final payment. The best contractors:
- •Check in periodically
- •Respond promptly to service calls
- •Honor warranty commitments
- •Provide honest advice about maintenance and eventual replacement
These relationships are worth maintaining. When your roof eventually needs replacement, you'll want a contractor you trust.
Making Your Decision
After gathering information, trust your judgment:
- •Who answered questions most thoroughly?
- •Who seemed most interested in understanding your needs?
- •Who has the most relevant experience?
- •Who do the references speak most highly of?
- •Who would you be most comfortable working with over time?
Price matters, but it's one factor among many. The contractor who will be there in 15 years when you have a problem is worth more than the one who saves you a few thousand today.
Take your time, do your homework, and choose carefully. Your roof will be protecting your building—and your investment—for decades.