Should You Replace Your Roof Before Installing Solar?
Short answer: the federal test is not “is my roof fine today” but will this roof need replacing during the life of the array. The Department of Energy puts panel life at 25 to 35 years, so a roof with 10 or 15 years left does not clear that bar — keeping it defers the cost rather than avoiding it, because the array has to come off when the roof goes. Below: what the roof-life numbers actually rest on, what a re-roof triggers under California code in 2026, and the one question the state tells you to ask before you sign.
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- The Department of Energy frames it as an assessment, not a number: the installer should determine whether the roof will need replacing during the life of the system, and if so, replace it first.
- Solar is planned around a 25 to 35 year service life — though that figure is an assumption from financial models, not measured survival. Published roof-life figures are trade expectations too: the most-cited study puts asphalt shingle at about 20 years flat, with no split between 3-tab and architectural.
- Replacing more than 50% of a roof in Los Angeles brings the whole roof to current code — which can mean a cool-roof product, and a Class A assembly in a Very High or High Fire Hazard Severity Zone. These rules are long-standing, not new.
- Rack-mounted panels do not exempt the roof under them from the cool-roof requirement. That exception is written for building-integrated PV only.
- No public agency publishes a detach-and-reset price. The CPUC tells you to ask your installer for it in writing — before you sign.
The one-minute version
Solar and roofing are two jobs that end up bolted together for decades. The Department of Energy states the test plainly in its guidance for commercial rooftop solar: before installing, the installer should assess the roof and determine whether it will need to be replaced during the life of the PV system — and where it will, owners are encouraged to replace it first. The document is written for building owners rather than homeowners, but the logic carries: the array and the roof share a service life whether the building is an office or a house.
DOE puts the operational life of a panel at 25 to 35 years, up from about 20 years in 2007. Worth knowing what that number is: a Berkeley Lab survey of nineteen developers, owners and consultants reporting the project life they assume in financial models for utility-scale plants. It is an expectation, not measured survival, and it does not come from residential rooftops — the same caveat this page applies to roof-life tables below.
Still, it is the planning horizon the industry works to, and against it a roof with only ten years of remaining life will need replacing well inside the array’s service life. When it does, the array comes off and goes back on at your expense. The counterweight is that re-roofing early writes off the unused life of the roof you have — so the real comparison is that write-off against the detach-and-reset it avoids, and it turns on numbers only a written quote and a roof assessment can supply.
The honest exceptions are real, though. Clay and concrete tile is expected to last the life of the house, and a federal estimate for California and the Southwest puts concrete tile at 40 to 50 years. A roof you have just replaced obviously stays. And in Los Angeles a re-roof carries code obligations that are easy to miss and that change the arithmetic in both directions.
How long the panels really last — and how much they fade
This is the number the whole decision hangs on, and the figure in general circulation is the most flattering one available.
You will read that panels degrade about 0.5% a year, so a 25-year-old array still makes 88% of its original power. That 0.5% is real, but it is the median of module-level measurements in the national laboratory’s literature compilation — and the mean for crystalline silicon in the same dataset is 0.8–0.9% a year, because the distribution has a long tail.
A house does not own a module, it owns a system. Measured at system level across a US fleet of 8.5 GW, the median performance loss is about 0.75% a year — but the same program separates recoverable soiling from true degradation, and with soiling excluded the fleet figure comes back to roughly 0.5% a year. Some of what looks like decline is dirt.
Narrowed to residential rooftops — a study of 503 systems, 387 of them homes — the median energy-yield degradation is 1.3% a year, and 2.1% with medium to heavy shade. That is a whole-system figure, and the authors are explicit that it should not be read as panel decline: it takes in foliage growth, unwashed soiling, inverter losses and balance-of-system deterioration, and they state that 0.5% a year remains the relevant number for the modules themselves. Much of the gap is recoverable by washing the array, trimming the tree and replacing an inverter.
Two limits on stretching that 1.3% across a lifetime: those residential systems averaged 3.9 years old when measured, so a 25-year projection runs six times beyond the observation window, and the same authors found the rate changing with age rather than holding flat. Taken at face value it would put a 25-year-old array near 70% of new; the module-level evidence points higher. The honest summary is a range, not a point — and note the tension with the 25-to-35-year planning life above, which comes from models assuming roughly 0.5–0.7% a year.
On climate, the published fleet numbers run by module temperature zone: about 0.48% a year in the coolest zone, 0.78% in the next, 0.88% in the hottest. Those come from commercial and utility-scale systems rather than rooftops, and the study places its own California systems, the Los Angeles area included, in the slower half of that range — not the desert end.
Warranties are a different thing again: a contractual floor with a claims process, not a forecast. Current premium modules warrant roughly 90–92% of nameplate at year 25, or 87–89% at year 30 on the newer 30-year terms. The lab that models system economics assumes 0.7% a year over a 30-year life.
Panel life from the U.S. Department of Energy, citing a Berkeley Lab survey of industry professionals. Degradation figures from the national laboratory formerly known as NREL: the Compendium of Photovoltaic Degradation Rates for the module-level median and mean, the PV Fleet Performance Data Initiative for the system-level median and its soiling-corrected result, and the fleet-scale residential analysis for the 1.3% energy-yield figure. Warranty percentages are from current manufacturer datasheets.
How long each roof really lasts
Worth knowing before you read any lifespan table, including this one: no national lab, federal agency, standards body or California agency publishes measured survival data for roof coverings. What exists are manufacturer and trade expectations. Here they are, labeled for what they are.
| Material | Published figure | What the figure rests on |
|---|---|---|
| Asphalt shingle | ~20 years | A single category. The most-cited life-expectancy study gives one asphalt row at 20 years and does not separate 3-tab from architectural. The asphalt roofing trade body publishes no service life at all, advising only that a roof over 20 years old is “a prime candidate for reroofing.” |
| Clay or concrete tile | “Lifetime” over 50 years | Also one undivided row — the study does not separate clay from concrete. For California specifically, a federal rehabilitation guide estimates concrete tile at 40–50 years in California and the Southwest, against 20–30 in the Southeast. |
| Slate | 50+ years | Same study. Rare on Los Angeles homes. |
| Wood shake or shingle | ~30 years | Academic in the City of Los Angeles, where wood shake and shingle roofs are banned outright, new or re-roof. |
| Metal, standing seam | No published figure | The life-expectancy study has no metal line at all except copper, which it calls “Lifetime.” The commonly quoted 40–70 years is a trade range with no independent source behind it. What is documented is the mounting advantage — see below. |
Figures from the NAHB/Bank of America Study of Life Expectancy of Home Components (February 2007) and, for concrete tile in California, the HUD Rehab Guide Volume 3: Roofs. Both are compilations of manufacturer and trade-association reports rather than field survival studies, and the NAHB study has not been updated since 2007 — it predates the current generation of laminated shingles and synthetic underlayments. For a counterweight from the other side of the market, the same HUD guide records that the Insurance Institute for Property Loss Prevention assumed an effective life of 17 years for an average asphalt shingle.
Two things sit outside that table. First, the underlayment. The roofing contractors’ association states that felt underlayment “service lives often fall short of primary roof covering materials’ service lives,” and that the underlayment should match the covering’s anticipated service life — which is precisely why it recommends non-felt underlayment beneath tile, metal shingle and slate. Under a tile roof the tiles will outlive the felt beneath them. That mechanism is well established; a specific number of years for it is not published by anyone citable, so treat any figure you are quoted as field judgement.
Second, standing seam. Its advantage is not longevity but attachment: the panels are held by concealed clips within the seams, so an array can be clamped to the seam without penetrating the weathering surface. That applies only to true concealed-clip standing seam — exposed-fastener metal panels still take penetrations — and penetration-free is not load-free: the uplift still travels through the clamp, the clip and into the structure.
So: replace it first, or not?
Run the federal test, then the local one. The federal test is about timing; the local one is about what a re-roof now would cost you in code compliance.
| Your roof | Does it pass the DOE test? | What that means in practice |
|---|---|---|
| Tile in sound condition, underlayment not yet aged out | Usually yes | The tile itself will outlast the array comfortably. The governing layer is the underlayment beneath it, not the tile, so older tile needs the same remaining-life assessment as asphalt — on the felt, not the surface. Where the underlayment is due, a reset before the array is the cheaper sequence. |
| Recently re-roofed, or a young architectural shingle roof | Yes | Keep it. There is no reason to spend on a roof that will see the array through. |
| Asphalt shingle with roughly 10–15 years of life left | Depends — have the remaining life assessed | The awkward middle, and note this row is about remaining life, not age: a ten-year-old architectural shingle roof in Los Angeles frequently has well over a decade left and passes comfortably. Where the remaining life really is short of the array’s, weigh a re-roof now at one mobilization against a re-roof later plus a detach-and-reset — and against the unused roof life you would be writing off by going early. That comparison needs a written quote for both, not a rule of thumb. |
| Asphalt shingle near or past 20 years, or visibly worn | No — on condition, not the calendar | Re-roof first. Doing it with the roof clear is cheaper and cleaner than doing it under an array. |
| Active leak, storm damage or soft decking | Assess before anything | Federal guidance treats roof condition as a gating assessment: FEMA advises a qualified roofing professional determine the suitability of an existing roof assembly before an array goes over it, and DOE tells homeowners to ask whether the roof needs repair first — and to settle in writing who is responsible if a leak develops later. |
The test itself is the Department of Energy’s: the installer should assess the roof and determine whether it will need replacing during the life of the PV system, and where it will, replacement beforehand is encouraged. There is no published “X years of remaining life” threshold from any agency — the closest is a screening line in a DOE low-income weatherization checklist asking for at least 10 to 15 years of shingle life remaining, which is an eligibility screen for that program, not a design rule.
What a re-roof triggers in Los Angeles — new for 2026
Most of this is long-standing: the 50% threshold and the cool-roof requirement have been in the code for years. What changed on January 1, 2026 is the wildfire side — the provisions were consolidated into a new code book and Chapter 7A stopped being the operative document.
Replace more than half the roof and the whole roof goes to current code
This is the threshold everything else hangs on. Re-roofing more than 50% of the roof area within any one-year period brings the entire roof up to the current code; at 50% or less, only the replaced portion has to comply. It counts as replacement whether you tear off or lay a new surface over the old one.
It matters here because a solar project usually means the whole roof, not a corner of it — so if you are re-roofing before solar, assume you are over the line.
Cool roof. Under the 2025 California Energy Code, a re-roof past that 50% line has to meet a reflectance requirement — but only in some climate zones, and Los Angeles straddles four of them. For a pitched roof the requirement applies in climate zones 8 through 15, which covers south and southeast Los Angeles, the basin and the San Fernando Valley — but not the coastal and west-side zone, and not Sunland-Tujunga. For a low-slope roof it reaches wider and asks for much more reflectance.
Several exits exist and most homeowners never hear about them. A pitched roof is relieved of the cool-roof product entirely by any one of: R-38 ceiling insulation, an attic radiant barrier, having no ducts in the attic in the applicable zones, or continuous insulation above or below the deck.
Tile deserves its own paragraph, because the common belief about it is wrong. There is a weight-based exception in the code, but it is a ballasted and thermal-mass provision that ordinary residential pitched tile does not reach — a re-roof with new tile is not automatically exempt. What genuinely escapes the requirement is a tile reset: lifting the existing tiles, replacing the underlayment beneath them and re-laying the same tiles. No new roofing product goes on, so there is nothing to certify. Since a tile reset is also the usual repair when the underlayment has aged out, that distinction decides real money — and it is worth settling with your roofer in writing before the job is scoped.
The exception that does not exist. There is a solar carve-out in the Energy Code, and it is narrower than the industry folklore suggests: roof area covered by building-integrated photovoltaic or solar thermal panels is not required to meet the reflectance and emittance minimums. Ordinary rack-mounted modules bolted above a conventional roof are not building-integrated. Shading your roof with panels does not relieve the roof beneath them. Even with solar shingles that mix live and dummy pieces, the state’s compliance manual holds that only the active photovoltaic area is exempt.
One more cost hides next to it: a low-slope re-roof over the 50% line also triggers continuous roof insulation across most of Los Angeles, and where a tear-off exposes the rafter bays the roof-ceiling assembly counts as altered and its own insulation minimum applies. Both are usually more expensive than the reflective surface itself.
Fire. Chapter 7A, the section everyone in the trade still names, no longer exists as the operative document. Its content was consolidated on January 1, 2026 into a new California Wildland-Urban Interface Code. For roofs the requirement is a Class A assembly, and the re-roof trigger is the same 50%-in-twelve-months test. But there is a second rule with no threshold at all: in a Very High or High Fire Hazard Severity Zone, any portion of a roof covering applied during an addition, alteration or repair has to meet at least Class A. In those zones even a patch is a Class A patch. Note the city’s express-permit bulletin words its own line more narrowly, for very high zones only — confirm which applies at your address.
Behind the code sits a statute that does not move with code cycles: Class A in a Very High Fire Hazard Severity Zone, Class B in most State Responsibility Areas, and Class C as the floor everywhere else in California — on the same more-than-50%-in-a-year test, with the installer obliged to certify the classification to the owner. Note also that the zone maps are moving: CAL FIRE issued recommended new Southern California maps in March 2025, the affected parcel count in Los Angeles is expected to rise, and the City cannot set a hazard level lower than the state recommends. A property outside a zone today may be inside one when the ordinance lands.
| Rule | What it means for you |
|---|---|
| Permit | A residential re-roof is an express permit with no plan check, issued online or at the counter. |
| Covering limits | The express categories are limited to a Class A or B covering weighing under 6 lb per square foot, with Class A required in a very high fire hazard severity zone and a CRRC-labeled cool-roof product where more than 50% of the roof is replaced. |
| Two layers is the ceiling | A recover is prohibited where the roof already carries two or more applications of any covering — at that point it is a tear-off. |
| Nothing goes over tile | A recover is prohibited where the existing covering is slate, clay, cement or asbestos-cement tile, and the city’s overlay table lists anything over a tile roof as not permitted. Tile is removed and reset or replaced, never covered. |
| No recover over a soaked or failed roof | Prohibited where the existing roof is water-soaked or too deteriorated to serve as a base — which is the code putting the same rule as the solar advice above. |
| Wood is out | Wood shake and wood shingle roofs are banned citywide, new or re-roof, with only a narrow small-repair path. |
From the 2025 California Energy Code (Title 24, Part 6), the 2025 California Wildland-Urban Interface Code (Title 24, Part 7), Health and Safety Code § 13132.7, and the City of Los Angeles building code and LADBS information bulletins effective January 1, 2026. Projects permitted before that date remain under the previous editions. Climate zone, fire hazard zone and slope decide which of these apply to your address — confirm yours with LADBS rather than assuming from a neighborhood name.
What getting the timing wrong costs
If the roof fails under the array, the array comes off and goes back on. Here is the honest state of what that costs.
No national laboratory, federal agency or California agency publishes a detach-and-reset price. That is not an oversight on our part — the CPUC handles the same question by telling homeowners to put it to the contractor, and its consumer guide gives you the wording: “Roughly how much will it cost to remove and re-install the panels if I need to replace my roof in the future, including inspection fees?” Ask it before you sign, and get the answer in writing.
What the federal side does document is the saving from sequencing the work together rather than apart: the Department of Energy cites roughly $25,000 to do a new roof and a new array as one project against nearly $30,000 doing them separately — about $4,000 saved on one mobilization. That is for a roof and a new array, which is exactly the decision this page is about.
Beyond that, expect a detach-and-reset to be quoted per panel, and expect the quote to rise with a steep pitch, with tile, and with a battery or conduit that has to be reworked. Our detach-and-reset guide walks the process, the permit and the re-inspection. Treat any dollar figure you read online as one company’s pricing, including ours — there is no industry benchmark to check it against.
Re-roofing “for solar” was never tax-deductible
Many homeowners re-roofed believing the roof would ride along on the 30% federal solar credit. It never did. The IRS position was explicit: traditional roofing materials and structural components do not qualify, because they primarily serve a roofing or structural function — and it named the parts, saying roof trusses and traditional shingles that support solar panels do not qualify. Creditable labor covered installing the solar equipment, not the roof beneath it.
There was one real exception, and it was about the product rather than the project: solar roofing tiles and shingles that generate electricity while serving as roofing did qualify, because the statute said such an item does not fail to count merely because it is a structural component. Asphalt shingles laid the week before an array never qualified, however necessary the re-roof was to the job.
All of it is academic for work done now. The credit does not apply to expenditures made after December 31, 2025, and an expenditure counts as made when the original installation is completed — so paying in December 2025 for a January 2026 installation earns nothing. A homeowner re-roofing before solar today gets no federal credit for the roof and none for the solar either. Our guide to the credit’s end has the detail.
Tile and shingle are different jobs
On asphalt shingle, mounting is straightforward: lag bolts into the rafters, flashed and sealed. If the roof is near end of life, replacing it before the array is comparatively cheap and clean.
Tile is where a roofer earns their keep. Tiles are brittle and have to be lifted, cut or swapped for tile hooks and flashings so the array sits watertight without cracking what surrounds it. Done badly, a tile install leaks. Because clay and concrete tile is expected to last the life of the house you generally keep it — but the felt beneath it is the layer on the clock, so the underlayment where the array will sit deserves a look first. In Los Angeles there is a further reason to get this right: tile can never be covered over, so a tile roof that fails is always a removal job.
This is the kind of work you want a licensed roofer on, not a panel crew. We hold a California C-39 roofing scope alongside the solar work under CSLB #1032379, so the inspection, the roof and the array are one accountable job — and if your roof does not need touching, that is what we will tell you.
Get a roof-and-solar assessmentFrequently asked
Should I replace my roof before installing solar?
Apply the test the Department of Energy uses in its rooftop-solar guidance: will the roof need replacing during the life of the PV system? Solar is planned around a 25 to 35 year service life — an industry planning assumption rather than measured survival — so a roof whose remaining life is well short of that will need replacing partway through, and the array comes off when it does. Note remaining life, not age: a ten-year-old architectural shingle roof in Los Angeles often has well over a decade left. Tile in sound condition passes, with the underlayment rather than the tile as the governing layer. And there is a cost on the other side of the ledger — re-roofing early writes off the unused life of the roof you have, which has to be set against the detach-and-reset it avoids.
How long does a roof actually last?
Less precisely than lifespan tables suggest. No national lab, federal agency or standards body publishes measured survival data for roof coverings — what circulates are manufacturer and trade expectations. The most-cited study gives asphalt shingle a single figure of about 20 years, with no split between 3-tab and architectural, and lists clay and concrete tile together as “Lifetime,” over 50 years. A federal rehabilitation guide puts concrete tile at 40 to 50 years in California and the Southwest specifically. For contrast, the same guide records an insurance-side assumption of a 17-year effective life for an average asphalt shingle.
Do solar panels really last 25 years?
Longer on current planning figures — DOE puts operational life at 25 to 35 years, though that comes from a survey of developers reporting the project life they assume in financial models for utility-scale plants, not from measured rooftop survival. What is usually muddled is the fade. The widely quoted 0.5% a year is a median of module-level power measurements. At system level a US fleet study finds about 0.75% a year, and roughly 0.5% once recoverable soiling is separated out. A study of residential rooftops finds 1.3% a year of energy-yield decline — a whole-system figure that includes tree growth, unwashed soiling and inverter losses, and its authors state plainly that 0.5% a year remains the relevant number for the modules themselves. Those systems averaged 3.9 years old when measured, so stretching 1.3% across 25 years is an illustration rather than a forecast.
Does adding solar exempt my roof from California's cool roof requirement?
No, not if the panels are ordinary rack-mounted modules. The Energy Code exception is written for building-integrated photovoltaic and solar thermal panels, and conventional modules bolted above the roof are not building-integrated — shading the roof does not relieve it. Even with solar shingles that mix live and dummy pieces, only the active photovoltaic area is exempt. And be careful with the common belief that tile is exempt by weight: the weight-based provision is a ballasted and thermal-mass rule that ordinary residential pitched tile does not reach. What does escape the requirement is a tile reset — lifting the existing tiles, renewing the underlayment and re-laying the same tiles — because no new roofing product is installed.
What does a re-roof trigger in Los Angeles in 2026?
Replacing more than 50% of the roof in a year brings the whole roof to current code — a long-standing rule, not a new one. Depending on your climate zone and slope that can mean a CRRC-labeled cool-roof product, and for a low-slope roof, added insulation. In a Very High or High Fire Hazard Severity Zone a Class A assembly is required, and there any portion of covering applied during an alteration or repair must be Class A regardless of how small. Los Angeles also caps you at two roofing layers, prohibits covering over tile entirely, and bans wood shake and shingle citywide. What actually changed on January 1, 2026 is the wildfire side: those provisions were consolidated into a new code book and Chapter 7A stopped being the operative document.
Can I claim the roof on my taxes if I re-roof for solar?
No, and you never could. The IRS held that traditional roofing materials and structural components do not qualify for the residential clean energy credit because they primarily serve a roofing or structural function, naming roof trusses and traditional shingles that support panels as non-qualifying. The one real exception was solar roofing tiles and shingles that generate electricity while serving as roofing. In any case the credit no longer applies to expenditures made after December 31, 2025, and an expenditure counts as made when installation is completed — so a 2026 job earns nothing federally for either the roof or the solar.
What will it cost to take the panels off later?
No public agency publishes a figure, which is itself worth knowing. The CPUC's consumer guide handles it by telling you to ask the contractor: “Roughly how much will it cost to remove and re-install the panels if I need to replace my roof in the future, including inspection fees?” Ask it before signing and get the answer in writing. Any dollar range you find online — including a contractor's own — is one company's pricing, not an industry benchmark. What DOE does document is the saving from combining the jobs: roughly $25,000 for a roof and new array together against nearly $30,000 done separately.
Is it safe to put panels on a roof that leaks?
Fix the roof first. Federal guidance frames this as an assessment rather than an absolute rule: FEMA advises that a qualified roof consultant or roofing contractor assess the condition of an existing roof assembly in determining whether an array is suitable over it, and DOE tells homeowners to ask whether the roof needs repair before installation — and to settle in writing who is responsible if a leak develops afterwards. Los Angeles code takes the same line for re-roofing, prohibiting a recover where the existing roof is water-soaked or too deteriorated to serve as a base.
Related reading
Sources & methodology
Figures on this page come from the primary sources below and, where noted, from Cali Energy calculations using the stated assumptions. Rates, incentives, and program terms change; each was verified September 10, 2026.
- U.S. Department of Energy — End-of-Life Management for Solar Photovoltaics (panel operational lifespan)
- Photovoltaic Degradation Rates — An Analytical Review (Jordan & Kurtz), national laboratory technical report
- Compendium of Photovoltaic Degradation Rates (Jordan, Kurtz, VanSant, Newmiller)
- CPUC — California Solar Consumer Protection Guide
- HUD — Rehab Guide Volume 3: Roofs (concrete tile service life in California)
- California Energy Commission — Building Energy Efficiency Standards (Title 24, Part 6)
- California Building Standards Commission — Title 24 codes, including the Wildland-Urban Interface Code (Part 7)
- California Health and Safety Code § 13132.7 — roof covering fire classification
- LADBS — express permits (residential re-roof)
- IRS — Residential Clean Energy Credit
- National Roofing Contractors Association — underlayment guidance
Not sure if your roof is ready for solar?
We're licensed for both roofing and solar (CSLB #1032379), so we inspect the roof before we ever design a system. Send us your roof's age and a recent bill and we'll tell you straight whether to re-roof first or go solar now.
Get a free estimatePrepared by Cali Energy, September 10, 2026. This article is for general educational purposes only and is not legal, tax, financial, engineering, or utility advice. Rates, incentives, codes, permit requirements, equipment specifications, prices, and program terms may change; figures and timelines are estimates, not guarantees. Confirm current requirements with the applicable utility, AHJ, program administrator, manufacturer, or a licensed professional. See our Content Disclaimer. Cali Energy · 19201 Parthenia St, Unit E, Northridge, CA 91324 · CSLB #1032379 (B, C-10, C-39)