Coat a commercial roof when the deck is sound, drainage works, leaks can be repaired first and a moisture survey shows the insulation is mostly dry. Replace it when wet insulation is widespread (GAF uses 25% of roof area as the point to consider tear-off), the deck is damaged or the roof is past its service life.
If your roof is aging and leaking in spots, the real question is whether a coating will buy you real years or whether you would be spending money on a roof that needs to come off. This guide covers the checks that decide it, what drives cost, the California cool roof rule for recoats, and the warranty and tax questions to settle before you take a recommendation to ownership.
OneRoof Solution has handled 635 commercial roofing jobs in California: 528 service and repair jobs and 107 larger reroof, overlay, coating and new roof projects. We have worked on commercial and industrial buildings since 2008, and we do not do homes.
Coating and replacement in plain terms
There are really three options on a low-slope commercial roof, and California’s 2025 Energy Code defines all three (California Energy Commission):
- Recoat (coating or restoration). A fluid coating applied to the existing roof. Done properly, it is a multi-step restoration, not a paint job: repairs, removal and replacement of wet material, seam reinforcement, cleaning so the coating will stick, then the coating system itself (GAF).
- Recover (overlay). A new roof covering installed over the prepared existing roof, without removing it. This is the middle option when the existing roof is too worn to coat but the layers underneath are dry and sound.
- Replacement (tear-off). The existing roof covering comes off, damaged material underneath is repaired, and a new roof goes on, usually with new insulation, cover board, membrane and flashings.
The five checks that decide it
These five checks, drawn from GAF’s coating guidance, decide it. Ask your contractor for the result of each.
- Structure and deck condition. Coatings are meant to protect an existing, structurally sound roof. GAF is direct about it: they are not intended or able to protect a failing roof. Any damage found has to be repaired back to a sound starting point first.
- Drainage and ponding. Some coatings are harmed by standing water, so drainage problems generally need to be fixed. Chemistry matters here: one independent guide notes that silicone handles ponding far better than acrylic (Commercial Roof Guide).
- Leaks found, repaired and dried. A coating may seal pinholes, but it is not a cure for a leaking roof. Citing its Liquid-Applied Roofing Manual, GAF says existing leaks must be found and repaired, and the repairs allowed to dry fully, before coating.
- Moisture survey. GAF’s guidance calls for a moisture survey to find wet material that must be replaced. If moisture is present in 25% or more of the roof area, a complete tear-off may be considered, and some warranties may require it.
- Remaining service life and adhesion. A coating cannot add life back to a roof that is already past its service life (GAF). An adhesion test on your actual roof confirms the coating will stick to the existing surface.
How we use these checks
Before we recommend a coating, we want a clear answer on all five checks, and we show you what we found. Our Rainshield Roof Care Program also includes infrared scans and scheduled inspections, which help spot wet areas early.
Red flags that mean replace, not coat
GAF lists these as signs that replacement is the better investment:
- Widespread moisture: wet insulation or soaked material throughout the roof.
- Structural issues: significant deck damage or major failure of the layers under the membrane.
- Persistent leaks: leaks that repairs cannot fix, especially in several areas.
- End of service life: a coating cannot restore life to a roof that has run out of it.
- Ponding that cannot be fixed: water that keeps pooling in the same places.
- Adhesion or detail problems that cannot be brought back to a sound starting point.
One industry guide also describes a “25% rule”: if more than about 25% of the roof area needs repair before coating, the project is close to replacement territory (Commercial Roof Guide). Treat it as a rule of thumb. The moisture survey and the deck tell you more.
What drives the cost of each option
Coating usually costs less, but as GAF notes, compare the same scope on the same roof.
Coating cost drivers (per GAF):
- Roof size
- How much preparation and repair is needed
- The coating system selected
- Number of coats and how thick they go on
- Labor to prep and install
Replacement cost drivers (per GAF):
- Tear-off and disposal
- New materials: insulation, cover board, membrane, flashings and accessories
- Installation labor
- Downtime and site logistics
For national context only, one independent guide puts installed coatings at about $2.50 to $5.00 per square foot and tear-off replacement at about $8 to $16 or more per square foot, depending on system, insulation and market (Commercial Roof Guide, updated March 2026). These are outside figures, not OneRoof Solution prices. We quote every roof after we see it. For a full breakdown of replacement bids, see commercial roof replacement cost per square foot.
Keeping your operation running
For food plants, cold storage, wineries and busy warehouses, downtime can cost more than the roof. A coating usually avoids the open deck, tear-off noise and debris of a replacement, which has to be planned around production, stock and food safety zones. Either way, the work can be phased. On a recent two-phase overlay of a roughly 245,000 sq ft winery facility in Sonoma County, we sequenced the work so the client’s operations never stopped.
Coating types at a glance
This summary follows one independent guide’s comparison (Commercial Roof Guide) and is general guidance only. GAF notes that product choice depends on your existing roof type, location, climate and local code, and that an adhesion test confirms compatibility.
| Silicone | Acrylic | Polyurethane | |
|---|---|---|---|
| Ponding water | Excellent | Poor | Moderate |
| UV resistance | Excellent | Excellent | Good (with aliphatic top coat) |
| Impact resistance | Moderate | Low | Excellent |
| Recoating later | Needs primer | Easy | Good |
| Minimum application temperature | 35°F | 50°F | 40°F |
| Often chosen for | Ponding, hot climates | Budget projects, dry climates | Foot traffic, equipment, hail |
On “silicone vs elastomeric”: elastomeric just means flexible, and acrylic, silicone and polyurethane coatings are all elastomeric. The useful comparison is between chemistries, as above.
We are certified or authorized applicators for Carlisle, GAF, Duro-Last, Versico, Henry, CertainTeed and American Standard Coatings. See the roof coatings and liquid-applied systems we offer and the facility types we serve.
California rules: when a recoat triggers cool roof requirements
Under California’s 2025 Energy Code (Title 24, Part 6, in effect since January 1, 2026), Section 141.0(b)2B says cool roof rules apply when a nonresidential roof is replaced, recovered or recoated over more than 50% of the roof area or more than 2,000 sq ft, whichever is less (California Energy Commission; Energy Code Ace, Section 141.0). A full-roof coating on almost any commercial building crosses that line.
What the code requires for low-slope roofs (less than 2:12):
- The product needs a 3-year aged solar reflectance of 0.63 or more and a thermal emittance of 0.75 or more, or a Solar Reflectance Index (SRI) of 75 or more, in every climate zone (CRRC 2025 Energy Code summary).
- Exceptions: a lower aged reflectance is allowed if the roof meets the maximum insulation U-factor in Table 141.0-B; roof area under built-in solar panels is exempt; and so are roofs carrying at least 25 lb per sq ft.
- Roofing products must be rated and labeled by the Cool Roof Rating Council (CRRC), and compliance is documented on the NRCC-ENV form. Minor repairs, such as fixing a leak, do not need a CRRC-rated product.
- The area of a roof recoat does not have to be insulated (Exception 4 to Section 141.0(b)2Bii). A recover or replacement that crosses the trigger generally does (Table 141.0-C, with some listed exceptions).
- Per the CEC, alterations to the roof of an unconditioned building do not trigger the cool roof rules. That can matter for some warehouses.
In practice, a white, CRRC-rated coating is often the way to comply, while a dark coating may not qualify. Permits may be required and local rules vary, so check with your building department before work starts.
Warranty and tax questions to ask before you sign
Is your current roof still under warranty? Check the warranty document before you coat (GAF). Carlisle’s Golden Seal warranty, for example, excludes damage from the owner’s failure to use reasonable care in maintaining the roof, and from alterations or rooftop additions made without Carlisle’s written authorization (Carlisle warranty PDF). Terms vary, so get your manufacturer’s answer in writing.
What warranty comes with the coating? Ask who issues it (the manufacturer or the contractor), how long it lasts, what it covers and what maintenance it requires. When we quote a coating, we spell out the warranty options for that system in writing.
Is it a deductible repair or a capital improvement? Some roofing sites say coatings are always deductible maintenance. It is not that simple. Under the IRS tangible property rules, whether roof work can be deducted as a repair or must be capitalized depends on whether it is a betterment, a restoration or an adaptation of the property (26 CFR 1.263(a)-3; IRS overview). The answer depends on your facts. Ask your CPA before you count on a deduction. This article is not tax advice.
Real examples from ORS projects
Replacement and restoration on one site: American Inc. office and shop buildings, Visalia. We tore off the old gravel built-up roof. On about 75,000 sq ft we installed a FiberTite fleece-back membrane, and on about 25,000 sq ft a Carlisle fluid applied acrylic restoration system, about 100,000 sq ft in all (see the project).
Recover: a Sonoma County winery. On a roughly 245,000 sq ft winery facility, we installed an overlay in two phases, scheduled so the client’s operations never stopped.
What we look for before recommending a coating:
- Sound deck and working drainage
- Leaks repaired and dried
- Wet areas mapped and limited
- Adhesion test passed
- Existing warranty and Title 24 scope checked
Browse more recent projects.
FAQ
Is a roof coating any good on a commercial roof?
Yes, on the right roof. GAF says a coating can extend the life of a structurally sound low-slope roof at lower cost and disruption than a tear-off. On a wet, failing or worn-out roof, it is wasted money.
How long does a commercial roof coating last?
One independent guide puts most commercial coatings at 10 to 20 years, depending on chemistry, thickness and climate (Commercial Roof Guide). The warranty term on your specific system is the better planning number.
Can you coat a leaking roof?
Not as a fix. GAF says leaks must be found, repaired and allowed to dry fully before coating. A coating may seal pinholes, but it will not stop a real leak.
What is the best roof coating for a flat roof?
It depends on the roof. Silicone handles ponding, acrylic suits roofs that drain well, and polyurethane suits heavy foot traffic. The existing roof, the climate and an adhesion test decide it.
Will a coating void my roof warranty?
It can. Many warranties exclude work done without the manufacturer’s written OK. Get written approval before coating a roof that is still under warranty.
Does recoating a roof in California trigger Title 24 cool roof rules?
Usually. If the recoat covers more than 50% of the roof or more than 2,000 sq ft, whichever is less, the coating must be CRRC-rated and meet the reflectance minimums. Unconditioned buildings are not covered, and the recoated area does not have to be insulated.
Is a roof coating tax deductible?
It depends on whether the work counts as a repair or an improvement (a betterment, restoration or adaptation) under the IRS tangible property rules. Ask your CPA.
How do I know if my insulation is wet?
You usually cannot tell from the surface. An infrared or other moisture survey maps likely wet areas, and core samples confirm them.
Not sure if your roof qualifies for a coating?
Book a roof assessment. We check moisture, drainage, deck and adhesion, and tell you straight whether to coat, repair or replace. 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.
Already have leaks? Schedule a roof repair.