Most commercial roof replacements are priced per square foot. 2026 national cost guides put typical membrane jobs at about $5.50 to $8.00 per square foot installed. Your real number depends on tear-off or recover, wet insulation, deck repairs, the membrane and California code rules. Only a roof inspection and a line-item bid give you a price you can trust.
If you need a number for next year’s capital plan, or two bids are far apart, this guide explains what goes into a bid, which California rules change the scope, how long the work takes, and how to compare bids.
OneRoof Solution has replaced and repaired commercial and industrial roofs across California since 2008 (CA License #930054), from offices in Visalia and Napa. We work on commercial buildings only. We do not publish our own prices, because we quote every roof after we see it. The dollar figures below come from national cost guides, with the source and date named.
The short answer: national ranges and why California bids differ
Two 2026 national guides agree on the typical band:
- Paletz Roofing’s 2026 guide says commercial roofs cost about $4 to $12 or more per square foot installed, with most projects at about $5.50 to $8.00 (Paletz Roofing, September 2026).
- SquareDash gives the same $4.00 to $12.00 range, with most projects at $5.50 to $8.00 (SquareDash, April 2026).
Commercial Roof Guide, which draws on contractor bids in 38 states, puts the West Coast 20% to 35% above the national average, mainly because of labor costs, and names California’s Title 24 cool roof rules as one reason (Commercial Roof Guide, March 2026).
These are national guide figures, not OneRoof prices. They are useful for a first budget line, not a bid.
What you are actually paying for: the line items in a real bid
A good bid reads like a scope of work, not one big number. Use this list to check each bid you get:
- Tear-off and disposal, or recover. Is the old roof coming off, or is the new one going over it? (More on this below.)
- Wet insulation. How much wet insulation will be removed and replaced, and how was it found? See our guide to commercial roof leak detection.
- Deck repairs. Rusted steel deck or rotted wood shows up once the roof is off. Ask for a unit price (per sheet or per square foot) so repairs are priced fairly.
- Insulation and cover board. Type, thickness and how it is attached.
- Membrane. Type (TPO, PVC, modified bitumen or other), thickness in mils, and attachment (mechanically attached, adhered or fleece-back).
- Flashings, curbs, drains and edge metal. These details are where many leaks start.
- Rooftop equipment and solar. Lifting and resetting HVAC units, or removing and reinstalling solar panels. We can plan both together (our services).
- Permits, safety and access. Permits, fire safety for any heat work, cranes, staging, and working around your operations.
- Warranty. Who issues it, how long it lasts and what it covers.
Paletz Roofing also advises asking for tear-off, wet insulation, deck repairs, disposal and drainage as separate lines (Paletz Roofing, 2026). Buried in one labor line, they cannot be compared.
Recover or tear-off: the biggest price swing
A recover means putting a new roof over the old one. It skips most tear-off and disposal, so it usually costs less. Commercial Roof Guide says an overlay over one existing layer usually costs 15% to 25% less than a full tear-off (Commercial Roof Guide, March 2026).
But in California, a recover is not always allowed. The 2025 California Building Code, Section 1512.3, says a new roof cannot go over the old one when:
- the existing roof is water-soaked, or so worn out that it is not a good base for new roofing, or
- the roof already has two or more layers of roofing, or
- the existing roof is slate, clay, cement or asbestos-cement tile.
(2025 California Building Code, Section 1512.3, UpCodes; same section at GoCodeBook)
So the number of layers and how wet the insulation is decide whether a recover is even allowed. An infrared or core survey before bidding tells you which kind of bid to ask for.
California rules that add cost
Title 24 cool roof rules on a reroof
California’s 2025 Energy Code (Title 24, Part 6) has cool roof rules for nonresidential buildings. They apply when more than 50% of the roof, or more than 2,000 sq ft, whichever is less, is replaced, recovered or recoated (California Energy Commission, 2025 Nonresidential Cool Roofs). Almost every full reroof crosses that line.
For low-slope roofs, the new roof must have a 3-year aged solar reflectance of at least 0.63 and a thermal emittance of at least 0.75, or a Solar Reflectance Index (SRI) of at least 75. The code lists some exceptions. Roofing products must be rated by the Cool Roof Rating Council (CRRC directory).
What it means for cost: white TPO and PVC often comply (check the CRRC listing), while a dark surface may need a reflective cap sheet or coating. A reroof that crosses the trigger may also need added insulation. Your bid should say how it meets both.
Fire safety for heat work on the roof
The 2025 California Fire Code, Section 3305.10, says roofing work that uses heat-producing systems or other ignition sources must follow the code’s hot work chapter, and at least one multipurpose fire extinguisher must be kept on the roof being worked on (2025 California Fire Code, Section 3305, GoCodeBook). Torch-applied and hot asphalt systems carry this extra safety work. Ask each bidder how they will handle it on your building.
TPO roof cost per square foot
TPO is the most common membrane on California warehouses and offices. Here is what two 2026 guides say it costs:
| Source (date) | TPO range per sq ft | What the figure includes |
|---|---|---|
| SquareDash (April 2026) | $4.50 to $7.00 (60 mil) | Not stated in detail |
| Commercial Roof Guide (March 2026) | $6.50 to $9.50 (60 to 80 mil) | Membrane, insulation, standard flashings and labor. Excludes tear-off, permits and engineering |
| Commercial Roof Guide (March 2026) | $7.75 to $12.00 | Full tear-off and reroof with TPO |
Sources: SquareDash, Commercial Roof Guide. These are national figures, not OneRoof prices.
Why so far apart? Each figure includes different things, such as insulation or tear-off. That is the main lesson of this page: compare what is included, not just the price per square foot.
What moves a TPO price:
- Thickness. TPO comes in 45, 60 and 80 mil, and fleece-back sheets come in 100, 115 and 135 mil. Commercial Roof Guide says 80 mil TPO costs 20% to 30% more than 60 mil, and resists punctures better.
- Attachment. Mechanically attached, fully adhered or fleece-back adhered.
- Insulation and cover board under the membrane.
Which TPO build we recommend. For a big, simple Central Valley warehouse with light foot traffic, 60 mil white TPO over code-level insulation is a sound standard, with 80 mil worth pricing for extra toughness. For roofs crowded with equipment or walked by service crews every week, we recommend 115 or 135 mil fleece-back TPO adhered over a cover board, with walkway pads on every service path. Carlisle says its 115 mil FleeceBACK TPO has 33% greater puncture resistance than 60 mil TPO (Carlisle data sheet), and GAF calls fleece-back TPO especially suitable for high-traffic roofs (GAF).
Comparing membranes? Read TPO vs PVC vs EPDM and TPO vs modified bitumen.
Cost by building size and roof shape
Bigger, simpler roofs cost less per square foot. Setup, equipment and permits cost about the same on a small roof as a big one, so on a big roof those costs are spread across more square feet. Commercial Roof Guide’s 2026 TPO table shows this: about $9.00 to $11.50 per sq ft at 5,000 sq ft, falling to about $5.50 to $7.25 at 100,000 sq ft (Commercial Roof Guide, March 2026).
Shape matters too. Rooftop units, curbs, pipes, skylights and small roof sections all add labor, so a small roof packed with equipment costs more per square foot than an open warehouse roof.
How long a commercial roof replacement takes
For a 50,000 sq ft warehouse tear-off and new single-ply roof, plan on about 3 to 6 weeks of roof work in dry weather, plus a few weeks before that for permits, submittals and materials.
- The Roofing Brief puts a typical 50,000 sq ft single-ply install at 15 to 25 working days from crew arrival to substantial completion, not counting 4 to 8 weeks of paperwork beforehand, and says weather adds 15% to 30% (The Roofing Brief, 2026).
- JRH Construction puts 10,000 to 50,000 sq ft roofs at 2 to 4 weeks and 50,000 to 100,000 sq ft roofs at 4 to 8 weeks, and says a tear-off adds 30% to 40% compared with an overlay (JRH Construction, 2026).
Our own records match that pattern. On our recent tear-offs of about 57,500 and 74,900 sq ft, the scheduled windows ran roughly 7 to 11 weeks, because both ran through fall and winter. What stretches a schedule: rain (membrane cannot go down on a wet deck), deck repairs and wet insulation found once the roof is open, phasing around production lines or tenants, the number of rooftop units to flash, and lead times on specialty membranes. We set the schedule with you before work starts.
Can you write off a commercial roof replacement?
Often, in some form. A new roof on a nonresidential building, put in after the building was first placed in service, can count as “qualified real property” that the owner may elect to expense under Section 179 (26 U.S.C. 179(e)). For tax years beginning in 2026, the limit is $2,560,000, reduced once qualifying property placed in service goes over $4,090,000 (IRS Rev. Proc. 2025-32). Otherwise the roof is generally depreciated with the building (IRS Publication 946). Talk to your tax advisor. OneRoof does not give tax advice.
Repair, restore or replace: when replacement is the cheaper choice
If the membrane is sound and the insulation mostly dry, a repair or coating may buy years for less. Our guide on commercial roof coating vs replacement explains how to tell, and regular checks (see how often a commercial roof should be inspected) help you catch problems while they are still small.
Replacement is usually the better spend when the insulation is widely wet, the deck is damaged, the roof already has two layers, or repairs keep failing. If you just need a leak fixed, schedule a roof repair.
How to compare two roof bids: a 5-step checklist
- Same scope: same tear-off or recover, insulation, membrane and thickness.
- Wet areas found, not guessed: infrared, moisture scan or cores.
- Unit prices for deck repair, so hidden damage is priced fairly.
- Warranty in writing: manufacturer system or material only, how long, and who issues it.
- Schedule: how the crew will keep your plant, warehouse or tenants running.
Real ORS reroof projects
These are published on our recent California reroofs page. We do not share what they cost.
- Richmond industrial facility (130,000 sq ft): we tore off 65,000 sq ft of the old roof and installed a fully adhered DensDeck Prime cover board and Carlisle 115 mil FleeceBACK TPO. The old roof was past its service life and the damage went beyond what patching could fix, so we took it down to the deck and started the new system on a clean, sound base.
- American Inc. office and shop, Visalia (100,000 sq ft): we tore off an old gravel-surfaced built-up roof and installed a new single-ply roof and an acrylic coating system. The old roof was past its service life and its problems were beyond patching, so a full tear-off was the responsible choice.
- Visalia industrial office, new construction (27,000 sq ft): Carlisle 60 mil TPO over 2 inch ISO insulation.
We are certified or authorized applicators for Carlisle, GAF, Duro-Last, Versico, Henry, CertainTeed and American Standard Coatings, so manufacturer system warranties are available on qualifying roofs. Ask us about warranty options for your building. See the TPO, PVC and coating systems we install.
After your new roof is on, our Rainshield Roof Care Program helps protect the new roof and its warranty with scheduled inspections.
FAQ
How much does a commercial roof replacement cost per square foot?
2026 national guides put most commercial roof replacements at about $5.50 to $8.00 per square foot installed, with a wider range of about $4 to $12 or more (Paletz Roofing, SquareDash). Your price depends on tear-off, wet insulation, deck repairs, the membrane and California code. An inspection and a line-item bid give the real number.
How much does a TPO roof cost per square foot?
National 2026 guides range from $4.50 to $7.00 for 60 mil TPO (SquareDash) to $6.50 to $9.50 for 60 to 80 mil TPO with insulation but without tear-off (Commercial Roof Guide). The gap is mostly about what each figure includes.
Is it cheaper to put a new roof over the old one?
Usually, because you skip most tear-off and disposal. But California’s Building Code (Section 1512.3) does not allow a recover if the old roof is water-soaked or worn out, or if there are already two or more layers. A moisture survey tells you if a recover is an option.
How long does a commercial roof replacement take?
For a 50,000 sq ft warehouse tear-off and reroof, plan on about 3 to 6 weeks of roof work in dry weather, plus time beforehand for permits and materials. Rain, deck repairs, phasing around an occupied building and rooftop equipment can stretch it to 2 months or more. We set the schedule with you before work starts.
Budgeting a roof replacement?
Book a roof assessment. We will check your roof’s layers and wet insulation, tell you if a recover is allowed, and give you a line-item bid you can compare.
Already have bids? Send them to us and we will point out what is missing.
Call (855) 762-7663, or (707) 440-2351 for our Napa office, or email sales@1roofsolution.com. For a roof emergency, call our 24/7 line at (559) 697-6252.