How to Evaluate a Commercial Roofing Bid (Beyond the Bottom Line)

You've received three commercial roofing bids and the prices are wildly different. The lowest is tempting, but experience tells you something might be missing. The highest makes you wonder if you're overpaying. Here's how to evaluate commercial roofing bids like a professional — beyond just the bottom line number.

Scope Comparison: Are You Comparing Apples to Apples?

The most common reason bids differ dramatically is scope variation. One contractor may include full tear-off while another proposes a recover system. One may spec 3-inch insulation where another includes 4 inches. Before comparing prices, verify that each bid addresses:

• Tear-off vs. recover: A recover (installing over existing material) costs less upfront but may void manufacturer warranties or hide underlying damage
• Insulation type and thickness: More insulation costs more but reduces energy expenses for decades
• Membrane type and thickness: A 60-mil TPO costs more than 45-mil but lasts significantly longer
• Flashing details: Cheaper bids often skimp on wall flashings, curb flashings, and penetration details — the areas most likely to leak
• Deck repair allowance: Good bids include a per-square-foot allowance for decking discovered damaged during tear-off
• Edge metal and coping: Some bids exclude perimeter metal work, adding it as a change order later

Request a detailed scope document from each bidder. If a contractor can't provide line-item breakdowns, that's your first red flag.

Warranty Terms: The Details Matter

Not all warranties are created equal. A "20-year warranty" from one contractor may cover vastly different things than the same claim from another. Evaluate these warranty components:

• Manufacturer warranty vs. contractor warranty: Manufacturer warranties cover material defects. Contractor warranties cover workmanship. You need both.
• NDL (No Dollar Limit) coverage: The gold standard in manufacturer warranties. NDL warranties cover the full cost of repair or replacement without depreciation. Standard warranties may only cover a prorated material cost.
• Wind speed coverage: Some warranties exclude wind damage above certain speeds. In storm-prone regions, this matters enormously.
• Consequential damage coverage: Does the warranty cover interior damage caused by a roof failure, or only the roof repair itself?
• Transferability: If you sell the building, can the warranty transfer to the new owner? This affects resale value.
• Maintenance requirements: Most manufacturer warranties require documented regular maintenance. Understand what's required to keep coverage active.

Insurance Verification: Protecting Yourself from Liability

Every commercial roofing contractor should carry comprehensive insurance. But don't just ask — verify. Request certificates of insurance and confirm:

• General liability: Minimum $1 million per occurrence, $2 million aggregate. For larger projects, request $5 million or an umbrella policy.
• Workers' compensation: Covers injuries to workers on your property. Without this, YOU could be liable for a worker's injuries.
• Auto liability: Covers damage from contractor vehicles on your property.
• Additional insured endorsement: Your company should be listed as an additional insured on the contractor's policy for the duration of the project.
• Policy dates: Ensure coverage extends through the entire projected timeline plus potential delays.

Call the insurance company directly to verify active coverage. Certificates can be forged or outdated.

Red Flags That Should Disqualify a Bid

Certain warning signs indicate a contractor may deliver substandard work or disappear when problems arise:

• No physical office or address: Legitimate commercial contractors have established operations, not just a cell phone and pickup truck
• Pressure to sign immediately: "This price is only good today" is a sales tactic, not a legitimate business practice
• Large deposit requirements: Requesting more than 10-20% upfront before materials are ordered is unusual for established contractors
• No manufacturer certifications: To offer manufacturer warranties, contractors must be certified installers. Ask for documentation.
• Cannot provide local references: A contractor who can't name 5-10 completed commercial projects in your area likely lacks relevant experience
• Vague scope documents: Professional bids specify exact materials, quantities, and methods. "Re-roof building per inspection" is not a scope of work.
• No safety program: Commercial roofing is dangerous work. Contractors without documented safety programs, OSHA training records, and low EMR (Experience Modification Rate) pose liability risks.
• Subcontracting the work: If the company bidding the job will hand it to a subcontractor you've never vetted, you lose control of quality and accountability

Questions to Ask Every Bidder

Beyond reviewing documents, ask these questions directly:

• Who specifically will be the project manager, and how do I reach them?
• What is your crew's average tenure with your company?
• How do you handle unforeseen conditions discovered during tear-off?
• What is your process for quality control inspections during installation?
• Can I visit a current job site to see your crew's work in progress?
• What happens if the project falls behind schedule?

Making Your Decision

The best bid is rarely the cheapest, and it's not always the most expensive. The best bid clearly defines what you're getting, protects you legally, and comes from a contractor with verified capability and track record. Spend the time to evaluate properly — this decision protects your building for the next 20-30 years.