In this article 18 sections
- How Do You Compare Commercial Roofing Bids Fairly?
- How Many Bids Should You Get?
- Why Bids Vary So Much
- Line-by-Line Comparison Checklist
- How to Compare Labor, Schedule and Crew
- How to Compare Warranties Across Bids
- Check Insurance and Credentials Before You Choose
- Hidden Exclusions to Watch
- Smaller line items that still add up
- How to Level the Bids
- How to Negotiate Without Cutting Corners
- FAQs | Comparing Bids
- Why is one roofing bid so much lower?
- Should I pay a deposit?
- Is a roof consultant worth it?
- How long is a roofing bid valid?
- Do I have to accept the lowest bid?
- Get a Bid You Can Compare
How Do You Compare Commercial Roofing Bids Fairly?
On a San Antonio TPO job, insulation alone can swing the price by $1.00 to $3.50 per sq ft, so on a large roof two “TPO roof” bids can differ by tens of thousands of dollars. Here’s how to level them, from proposals we’ve seen across commercial roofing in San Antonio.
How Many Bids Should You Get?
Three. With two, you can’t tell which one is the outlier; with three or four, patterns appear. Tell bidders they’re competing and give them all the same written scope.
Why Bids Vary So Much
| Item | Typical San Antonio range / sq ft | Why it varies |
|---|---|---|
| TPO membrane installed | $5.28 – $8.16 | Thickness (45/60/80 mil), attachment, brand |
| Tear-off and disposal | $1.00 – $3.00 | Layers, gravel, wet material |
| Insulation | $1.00 – $3.50 | R-value and type required by code |
| Deck repair | Unit price | Unknown until tear-off |
Commercial Roof Guide (Mar 2026); Core Commercial Roofing (2026).
Line-by-Line Comparison Checklist
| Line item | What to confirm | Bid A | Bid B | Bid C |
|---|---|---|---|---|
| Roof system | Membrane type, thickness, color, brand | |||
| Attachment | Mechanically fastened, adhered or ballasted | |||
| Tear-off | All layers? Disposal included? | |||
| Insulation | Type, thickness, R-value, tapered for drainage? | |||
| Cover board | Included? Type and thickness? | |||
| Deck repair | Unit price per sq ft or per sheet | |||
| Flashings and curbs | All penetrations and walls? | |||
| Edge metal and coping | New, gauge, color, wind rating | |||
| Drains and gutters | New drains or strainers? Gutters? | |||
| Rooftop equipment | Lifting and reconnecting HVAC | |||
| Warranty | NDL or limited, years, wind rating | |||
| Permit and inspections | Included and pulled by contractor? | |||
| Schedule | Start date and duration | |||
| Exclusions | What’s specifically left out |
How to Compare Labor, Schedule and Crew
- Separate labor from materials: if materials are specified in your scope, labor differences become visible.
- Compare duration: a bid with half the schedule of the others is either under-scoped or has more crew; ask which.
- Ask about subcontractors: who will be on the roof, and are they insured and contracted to the roofer, not to you?
- Ask about safety: a very low labor price can mean weak fall protection and safety planning, which is your liability risk too.
- Confirm cleanup and disposal are included.
- Ask for the start date: a lower bid that can’t start for months may cost more in leaks and disruption.
How to Compare Warranties Across Bids
| Check | Why it matters |
|---|---|
| Manufacturer warranty type | NDL system (labor + materials) is worth far more than material-only |
| Term (years) | Longer terms usually require thicker materials and inspections |
| Wind speed and hail coverage | Low wind limits and hail exclusions shift risk back to you |
| Contractor workmanship term | Often 1 – 2 years; longer terms show confidence |
| Included or extra cost | Some bids add the warranty fee later |
Check Insurance and Credentials Before You Choose
- General liability (many owners require at least $1 – 2 million), workers’ comp and auto
- Hot-work coverage if torches or hot asphalt are used
- Certificates sent by the agent, naming you as certificate holder
- Manufacturer certification for the warranty being offered
Hidden Exclusions to Watch
- Deck replacement “by others” or with no unit price
- Wet insulation replacement not included
- HVAC disconnect and reconnect excluded
- Permits, crane or dumpster fees excluded
- Code-required insulation upgrades not mentioned
- Warranty that’s material-only, not labor and materials
Smaller line items that still add up
- Freight: is material delivery included?
- Storage: who pays for secure on-site storage on long jobs?
- Cleanup scope: roof only, or also parking lots, sidewalks and landscaping?
- Dumpsters and landfill fees: included or billed later?
- Safety record: ask for each bidder’s incident rate (TRIR); the roofing industry average cited by Property Manager Insider is about 4.4.
How to Level the Bids
- Write one scope (or have a roof consultant write it) and send it to every bidder.
- Ask each bidder to price the scope plus any alternates separately.
- Request unit prices for deck and insulation replacement.
- Normalize the bids in the checklist above.
- Interview the top two and check references.
Get a baseline with the commercial roof replacement cost calculator, or see commercial roof replacement in San Antonio and commercial roof repair in San Antonio.
How to Negotiate Without Cutting Corners
Negotiate scope and terms, not just price. Options that lower cost without weakening the roof:
- Flexible start date during a contractor’s slower season
- Phasing the work over two budget years
- Alternate products of equal performance
- Agreed unit prices for hidden damage, so contingencies don’t inflate the bid
- Coating or recover instead of tear-off, where the roof qualifies
Avoid lowering membrane thickness, insulation or cover board just to hit a number. Those choices show up as shorter roof life.
FAQs | Comparing Bids
Why is one roofing bid so much lower?
Usually a thinner membrane, less insulation, no cover board, missing flashing or edge metal, or a weaker warranty. Ask the low bidder what’s not included.
Should I pay a deposit?
A modest deposit for materials is common on commercial jobs, with the rest tied to milestones. Avoid large upfront payments.
Is a roof consultant worth it?
On large or complex roofs, often yes. A consultant writes a single scope, reviews bids and inspects the work, which can save more than their fee.
How long is a roofing bid valid?
Commonly 30 to 60 days, since material prices change. Check the expiration date before comparing.
Do I have to accept the lowest bid?
Private owners can choose any bid. Public entities and some nonprofits follow procurement rules, many of which allow best-value selection rather than lowest price. Check your organization’s requirements before you issue the bid.
Get a Bid You Can Compare
Our proposals are itemized line by line, so you can drop them straight into the checklist above.
- Free roof assessment across San Antonio, including Westover Hills, commercial roof replacement in Stone Oak and Converse
Book your free roof inspection in San Antonio or see flat roofing in San Antonio.
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