What to Look for in a Flat Roofing Contractor
How to Choose the Right Professional for Your Commercial Building
Hiring the right commercial flat roofing contractor is one of the most important decisions a property owner or facility manager can make. A flat roof isn’t just a surface — it’s a complete protection system that safeguards your building, equipment, inventory, and long-term operations.
This guide outlines the qualities, skills, and standards that reliable commercial roofers must meet.
1.
Look for True Commercial Experience
Commercial roofing is a specialized field. It requires different tools, techniques, drainage planning, and safety requirements than residential roofing.
A qualified contractor should:
Have experience with large commercial buildings
Understand drainage and tapered insulation systems
Know how to work around HVAC units and multiple penetrations
If they primarily do residential work, they’re not the right fit for a large commercial building.
2
Verify Licensing & Insurance
This protects both your building and your legal liability.
You should confirm:
State-required roofing license
General liability insurance
Workers’ compensation
Up-to-date safety certifications
Defensive or aggressive replies to customers
3
Check Their Google Reviews
A strong online reputation shows consistency and reliability.
Look for:
High overall rating (4.5+ preferred)
Detailed customer feedback mentioning communication, professionalism, and clean work
Photos posted by customers
How the company responds to negative reviews
Consistently good reviews mean the contractor treats customers well before, during, and after the project.
4
Evaluate Their Website
A polished, well-organized website demonstrates professionalism, structure, and transparency.
A trustworthy commercial roofing website should include:
Clear service descriptions
Photos of real commercial projects
About/credentials page
Safety information
Easy-to-find contact details
Evidence of documented work (photos, maintenance programs, etc.)
A sloppy or outdated website often reflects sloppy work habits.
5
Ask About Their Safety Standards
Commercial roofing requires strict adherence to OSHA safety protocols.
A reliable contractor will:
Maintain written safety programs
Use fall-protection equipment
Train crews regularly
Follow clear jobsite procedures
Provide safety documentation on request
Professionalism begins with safety.
6
Evaluate Their Flashing & Detail Work
Most flat roof leaks happen at the details, not the open field.
A true professional will:
Reinforce all penetrations
Ensure clean, consistent seams
Provide photo documentation
Use correct materials and techniques for transitions
Poor flashing is the #1 cause of commercial roof failure.
7
Review Their Drainage Knowledge
Water is the greatest threat to flat roofs.
Skilled contractors understand:
Proper roof slope
Internal drain systems
Tapered insulation design
Scuppers and overflow protection
How to eliminate ponding
If a contractor cannot clearly explain drainage, they don’t fully understand flat roofing.
8
Confirm Material Knowledge
Even though this page is not product-focused, roofers must understand:
Interests:
How membranes respond to temperature
How seams hold up under stress
Which systems are best for large buildings
VOC, chemical, and grease exposures (restaurants, factories)
Long-term maintenance requirements
Experts recommend—not push—specific systems based on your building’s needs.
9
Look for Clear Communication
Commercial building owners need clarity, not confusion.
Signs of a good communicator:
Quick responses
Detailed and transparent quotes
Clear timelines
Explains findings and solutions
Sends updates during the project
A roofer who communicates well is almost always a roofer who installs well.
10
Ask About Warranties & Documentation
Professional contractors stand behind their work.
They should provide:
Manufacturer warranties
Workmanship guarantees
Inspection reports
Photo logs
Maintenance recommendations
Documentation protects your investment for decades.
11
Get References & Recent Project Photos
A strong contractor has nothing to hide.
Ask for:
Photos of recent commercial jobs
Contact info for past clients
Examples of maintenance programs
Before/after images
If they hesitate, that is a red flag.
12
Choose Contractors Who Offer Long-Term Service
You don’t want a one-and-done contractor.
The best companies offer:
Annual inspections
Seasonal maintenance
Emergency repair services
Long-term documentation of your roof’s condition
Commercial roofs last longer when cared for regularly.
Key Takeaways
Look for contractors with real commercial experience
Check their Google reviews and online reputation
A polished website signals professionalism
Verify licensing, insurance, and safety standards
Inspect their flashing, drainage, and detail work
Expect clear communication and strong documentation
Choose roofers who offer long-term support
A reliable contractor doesn’t just install a roof — they protect your building, people, and operations.
