When it's time to repair or replace a commercial roof, most property managers do the right thing — they get multiple bids. But once those proposals come in, many aren't sure what they're actually comparing.

One bid comes in at $40,000. Another at $62,000. And a third at $55,000. Which one do you choose?



The cheapest bid isn't always the best deal — and the most expensive one isn't always the highest quality. Knowing what to look for can save you from costly mistakes, failed installations, and contractor disputes.

Here's how to evaluate commercial roofing bids the right way.

Why Bids Vary So Much

Before comparing numbers, it's important to understand why commercial roofing bids can differ by tens of thousands of dollars.

Bids vary based on:

Roofing materials specified (TPO vs. EPDM vs. modified bitumen)

Thickness and manufacturer of materials

Scope of work (tear-off vs. overlay)

Warranty terms included

Labor quality and safety standards

Whether proper drainage, flashing, and insulation are included

Insurance coverage carried by the contractor

A bid that looks cheaper on paper may be cutting corners in one or more of these areas.

1. Make Sure You're Comparing the Same Scope of Work

The most common mistake property managers make is comparing bids that aren't actually for the same job.

Ask each contractor to specify:

Is this a full tear-off and replacement, or an overlay?

What roofing system is being installed? (TPO, EPDM, modified bitumen?)

What thickness is the membrane?

Who is the material manufacturer?

What happens to the old roofing material — is disposal included?

Does the bid include all flashing, edge metal, and penetrations?

If the bids are structured differently, you can't compare them fairly on price alone.

2. Look at the Warranty — Both Manufacturer and Workmanship

A roofing warranty is only as good as what it actually covers. There are two types to look for:

Manufacturer Warranty — Covers defects in the roofing materials themselves. Typically 10–30 years depending on the system and manufacturer.

Workmanship Warranty — Covers the contractor's installation. This is where many low-bid contractors fall short.

Ask each bidder:

What manufacturer warranty comes with the materials?

What workmanship warranty do you offer?

Is the manufacturer warranty a "no-dollar-limit" (NDL) warranty, or does it cap coverage?

A contractor who is certified by the manufacturer to offer full warranty coverage is a major differentiator — and it's worth paying for.

3. Verify Insurance and Licensing

This one is non-negotiable.

Before accepting any bid, confirm the contractor carries:

General Liability Insurance — Protects your property if damage occurs during the project

Workers' Compensation Insurance — Protects you from liability if a worker is injured on your roof

Proper licensing for the state of Missouri or Illinois, depending on your property location

Ask for certificates of insurance — not just a verbal confirmation. A low bid from an uninsured contractor could cost you far more if something goes wrong.

4. Evaluate Experience with Your Roof Type

Not all commercial roofing contractors specialize in all systems. A contractor who primarily does residential work or mostly handles metal roofs may not be the right fit for a flat TPO system.

Ask each bidder:

How many commercial roofs of this type have you installed?

Can you provide references from similar projects in the St. Louis area?

Are you certified by the manufacturer of the materials you're proposing?

Experience with your specific roof type and local climate conditions — including St. Louis's freeze-thaw cycles, storm exposure, and humidity — matters more than a low price.

5. Watch Out for These Red Flags

A low bid can sometimes signal a problem rather than a deal. Be cautious if a contractor:

Asks for a large upfront payment before work begins

Can't provide proof of insurance

Offers no workmanship warranty

Is vague about materials or manufacturers

Has no local references or online presence

Pressures you to sign immediately

Reputable commercial roofing contractors are transparent, patient, and happy to answer questions. Hesitation on any of these points is a warning sign.

6. Ask About Project Management and Communication

A commercial roof replacement is a significant project that affects your building operations, tenants, and schedule. Before signing, ask:

Who will be on-site managing the project day to day?

How will you communicate updates and progress?

How do you handle unexpected issues discovered during tear-off?

What is the estimated timeline from start to completion?

A contractor who gives clear, confident answers to these questions is far more likely to deliver a smooth project than one who is vague or dismissive.

7. Total Cost of Ownership — Not Just the Upfront Price

The cheapest bid today can become the most expensive decision over time.

When evaluating total value, consider:

Lifespan of the proposed system — A higher-quality membrane may last 5–10 years longer

Energy efficiency — Reflective roofing systems like TPO can reduce cooling costs in summer

Maintenance requirements — Some systems require more upkeep than others

Warranty protection — A strong warranty can save significant money on future repairs

A $10,000 difference in upfront cost is small compared to the cost of a premature replacement or an uncovered failure years down the road.

A Simple Bid Comparison Checklist

Use this when reviewing proposals side by side:

☐ Same scope of work (tear-off, materials, disposal)?

☐ Manufacturer and product specified?

☐ Membrane thickness listed?

☐ Flashing, edge metal, and penetrations included?

☐ Manufacturer warranty length and type?

☐ Workmanship warranty offered?

☐ Proof of liability and workers' comp insurance?

☐ Contractor is manufacturer-certified?

☐ Local commercial references available?

☐ Project timeline and communication plan outlined?

Work With a Contractor You Can Trust

Comparing bids takes time — but it protects your building, your budget, and your peace of mind.

At Taylor Roofing, we believe in transparent proposals and honest recommendations. We'll walk you through every line of our bid, explain exactly what materials we're using and why, and back our work with strong warranty coverage.

We've been serving commercial property owners and managers throughout the St. Louis Metro Area for decades — and we're happy to answer any questions, even if you're still in the comparison stage.

✔ Detailed, transparent proposals

✔ Manufacturer-certified installation

✔ Full liability and workers' comp insurance

✔ Strong workmanship warranty

✔ Local St. Louis references available

Ready to Get a Bid You Can Trust?

Schedule a free estimate with Taylor Roofing today. We'll inspect your roof, explain your options, and give you a clear, detailed proposal — no pressure, no surprises.