Bidding Commercial Roof Jobs: Take-Off, Spec, and Bid Day

Commercial roof bidding is a different sport than writing a residential estimate in your truck. The deals are bigger, the specifications are tighter, and the margin for error is smaller. One bad take-off on a 250,000 square foot TPO job can eat your entire profit and then some. Here is how professional commercial roofing estimators actually bid.

The Commercial Bid Stack

Every commercial bid has 5 pieces. Miss one and you lose money.

1. Take-off: Accurate square footage, perimeter, penetrations, and details
2. Specification response: Meeting or improving on the architect and consultant spec
3. Cost stack: Material, labor, equipment, overhead, profit
4. Bond and insurance: Premium costs baked into the bid
5. Terms and exclusions: What you are not responsible for

Take-Off Accuracy

Your take-off determines whether the bid has a prayer of profit. Three methods in order of accuracy:

On-Roof Measurement

Best for jobs under 50,000 square feet or where access is free. Walk the roof with a measuring wheel and laser. Count every penetration by type (pipe, HVAC curb, skylight, scupper). Photograph every detail. Time cost: 2 to 6 hours per 50,000 sqft. Accuracy: 98 to 100 percent.

Drone Aerial with Ground Truthing

Best for jobs 50,000 sqft and up. DJI Mavic or Autel with RTK module. Fly a grid pattern at 150 to 200 feet. Software like DroneDeploy or Pix4D stitches to an orthomosaic. Ground-truth with a 30-minute walk-around. Time cost: 3 to 5 hours. Accuracy: 95 to 99 percent.

Plan-Based Take-Off

On new construction or major renovation, you work from architect drawings. PDF plans into PlanSwift, Bluebeam, or On-Screen Takeoff. Count everything. Cross-check with the architect spec book. Time cost: 6 to 16 hours depending on complexity. Accuracy: depends on plan quality.

Specification Response

Commercial specs are written by roof consultants and architects. They specify the membrane, the insulation, the fasteners, the warranty, the flashing details, and the installation sequence. You either meet the spec, propose an equal, or take a deduct.

Common spec traps:

• Warranty length: 20-year manufacturer warranty costs more than 15-year. Do not bid 15 if the spec requires 20.
• Membrane thickness: 60 mil TPO vs 80 mil vs 90 mil: 15 to 35 percent material cost difference.
• Insulation R-value: R-25 vs R-30 vs R-38 changes your layer stack and cost significantly.
• Fastening pattern: mechanically attached vs fully adhered vs ballasted.
• Tapered insulation: critical for drainage and a major cost driver.

The Cost Stack

Typical $500K commercial TPO replacement on a 75,000 sqft roof.

LineCostPercent of bid TPO membrane (60 mil)$52,50010.5% Polyiso insulation (R-30, tapered)$97,50019.5% Cover board (1/2 inch)$22,5004.5% Fasteners, adhesive, sealants$18,0003.6% Flashing metal$15,0003.0% Labor (crew plus helper)$140,00028.0% Tear-off and disposal$37,5007.5% Crane and equipment rental$18,0003.6% Bond and insurance$12,5002.5% Safety, OSHA, permits$8,5001.7% Overhead (15%)$63,00012.6% Profit (target 15%)$15,0003.0% Total bid$500,000100%

Bond Requirements on Public Projects

Public work (schools, municipal, state, federal) almost always requires payment and performance bonds at 100 percent of contract value. Private commercial: bonds required when specified, usually on jobs over $250K.

Bond cost: 0.75 to 2.5 percent of contract value depending on your bonding company rating. A $500K bond at 1.5 percent is $7,500. Build this into every bid that might require a bond.

Bid Day Execution

Bid day is the last 24 to 72 hours before submission. Your subs and suppliers wait until the last moment to give you their final prices. You have to scramble, normalize the numbers, and produce a clean bid package.

The Bid Checklist

• Final material quote (locked for 30 days)
• Final sub quotes (tear-off, sheet metal, crane)
• Bond premium confirmation
• Insurance certificate with exact additional insureds named
• Schedule of values
• List of equals and substitutions
• Exclusions and clarifications
• Signed bid form
• Bid bond (separate from performance bond)

If bid documents require electronic submission through a portal (Procore, Building Connected, municipal e-bid), practice uploading 24 hours early. A failed upload at 1:59 PM when bids are due at 2:00 PM means your bid is dead.

Track your bids, wins, and loss ratios in RoofKnockers to refine your pricing over time. Target a 15 to 25 percent hit rate on commercial bids.

Post-Bid Analysis

Win or lose, review every bid. If you won, were you the low bid by 3 percent (good) or 18 percent (you left money)? If you lost, what did the winner bid and what did they cut that you included?

Commercial roofing trade associations often publish bid results on public projects. Pull these after every public bid and run a spreadsheet of your position vs winners. For context on how commercial fits into your full business, read commercial vs residential business models. For pricing your tools to estimate bigger pipelines, see RoofKnockers pricing.

FAQ

How accurate does my bid need to be?

Plus or minus 2 to 3 percent on cost. On a $500K job, a 3 percent miss is $15,000, which is your entire profit. Tight bid discipline is the difference between commercial contractors who grow and those who fold.

Should I bid every commercial opportunity?

No. Target a 20 percent hit rate. If you are winning 50 percent you are leaving money. If you are winning less than 10 percent, you are bidding jobs that are not right for you. Qualify ruthlessly.

When do I need a dedicated commercial estimator?

When you are bidding more than 2 jobs per month over $100K. Before that, the owner or lead PM can handle estimating alongside other duties. A dedicated commercial estimator costs $75K to $115K plus bonus.