Commercial roofing estimates aren't just bigger residential estimates. The pricing logic, attachment methods, manufacturer specs, and bid format are fundamentally different. Contractors who try to scale residential estimating habits into commercial work either lose money on every job or never win one.
- →Commercial pricing is per-square-foot, not per-square (100 SF).
- →Attachment method drives 40% of total cost — mech vs. fully adhered vs. ballasted.
- →Insulation R-value & tapered systems often dwarf the membrane line item.
- →Manufacturer NDL warranties require certified installer + spec adherence.
- →Commercial bids are won on completeness, not just price.
The three primary commercial systems
TPO (thermoplastic polyolefin)
TPO dominates new commercial low-slope work — roughly 50% market share. Heat-welded seams, white reflective surface (Energy Star), 60-mil and 80-mil thicknesses common. Available mechanically attached, fully adhered, or induction-welded (RhinoBond).
EPDM (ethylene propylene diene monomer)
Black rubber roofing — 40+ year proven track record, exceptional cold-weather performance, simpler installation. Seams are taped or tape-and-primer. Ballasted EPDM is still common on flat industrial roofs where weight isn't a concern.
Modified bitumen (mod-bit)
Asphalt-based, reinforced with polyester or fiberglass. Two-ply or three-ply, applied via torch, hot-mop, cold-adhesive, or self-adhered. Common on small commercial, residential flat-roof additions, and tear-off-and-replace work where the existing system was BUR.
Per-square-foot pricing — typical 2026 ranges
| System | Material/SF | Labor/SF | Total installed/SF |
|---|---|---|---|
| 60-mil TPO mechanically attached | $1.85 | $2.10 | $5.40 – $6.80 |
| 60-mil TPO fully adhered | $2.40 | $2.80 | $6.80 – $8.40 |
| 80-mil TPO induction-welded | $2.65 | $2.95 | $7.40 – $9.20 |
| 60-mil EPDM mechanically attached | $1.65 | $2.00 | $4.90 – $6.20 |
| 60-mil EPDM fully adhered | $2.10 | $2.70 | $6.20 – $7.80 |
| 2-ply mod-bit torch | $2.95 | $3.40 | $7.80 – $9.60 |
| 2-ply mod-bit cold adhesive | $3.20 | $3.10 | $7.90 – $9.40 |
These ranges assume 50,000+ SF jobs. Smaller jobs (under 10,000 SF) carry 25–40% higher per-SF costs because of mobilization and minimum crew sizing.
Insulation: the line item that swings the bid
On a fully adhered TPO recover with a tapered ISO system to meet R-30, the insulation package can be larger than the membrane package. A typical breakdown:
- Polyiso (R-6 per inch): $0.95 – $1.25 per SF per inch installed
- Tapered polyiso (1/2" per ft slope): adds 30–55% over flat polyiso
- Cover board (1/4" or 1/2" gypsum-based, e.g. DensDeck): $0.85 – $1.15 per SF
- Adhesive (low-rise foam): $0.40 – $0.65 per SF
On a 50,000 SF tapered polyiso to R-30 with cover board, the insulation alone can be $4.50–$6.00 per SF — often more than the TPO membrane.
Attachment method drives the spec
Mechanically attached
Fastest install, lowest material cost, but requires structural deck (steel or wood). Wind uplift design must be calculated per FM Global I-90 / I-120 / I-150 rating.
Fully adhered
Smoother appearance, better wind performance, required on most concrete decks. Bonding adhesive or low-rise foam. Slower install, higher material cost.
Induction-welded (RhinoBond)
Plates are mechanically fastened to the deck, then membrane is laid over and welded to the plates with an induction tool. Combines mechanical attachment with adhered appearance. Premium pricing.
Warranty & manufacturer requirements
Commercial work usually carries a manufacturer NDL (No Dollar Limit) warranty — 15, 20, or 30 years. To issue NDL, the manufacturer requires:
- Certified / authorized installer status (annual training + minimum volume)
- Pre-job submittal package approval
- Manufacturer-spec'd accessories (no mixing brands)
- Inspection by manufacturer field rep at completion
- Warranty fee ($0.05 – $0.18 per SF depending on term)
What separates a winning commercial bid
Completeness
Property managers and GCs reject bids that don't include a complete scope letter, manufacturer submittal, attachment plan, and qualifications package. Price-only bids get tossed.
Schedule
Include a phased schedule showing crew size, daily SF target, and weather contingency. This signals operational maturity.
References & insurance
Three comparable-scope project references (within last 24 months), $2M general liability minimum, $5M workers comp. Pre-qualify with the GC's bond company if it's a bonded job.
Common bid mistakes that lose money
- Bidding from drawings without a site visit (always 5–15% miss on existing-conditions allowances)
- Using residential mark-ups (commercial O&P is 10–15%, not 25%)
- Forgetting equipment rental (boom lifts, debris chutes, on-roof carts)
- Underestimating wind-uplift fastener density (FM I-120 vs I-60 doubles fastener count)
- Missing tapered insulation calc (assuming flat insulation when drainage required)
Estimating commercial faster
RoofGenius supports both residential and commercial estimating with system-specific templates for TPO, EPDM, and mod-bit. Pricing books are loaded by attachment method and insulation system, so a 50,000 SF TPO recover with R-30 tapered ISO comes together in 8–10 minutes instead of an afternoon. See the commercial workflow.