Remaining covering life
The only input that produces a real verdict. Everything else is context. Ask a roofer for it in years, and ask what they based it on.
HyreSolar tools
Should You Re-Roof Before Solar?
One comparison: how long the covering has left against how long the array will be there.
Panels last longer than most roof coverings. If the covering fails first, someone has to remove the array, re-roof and reinstall it, and that is a real cost nobody quotes at the outset. This tool makes the comparison explicit. It is a rule of thumb, not an inspection.
What this returns at the defaults
If your covering has fewer years left than the array term, the answer is to replace it first. A roof with 15 years left under a 25-year array means a removal and reinstallation somewhere around year 15. A covering with 25 or more years left can outlast the term. If you have not had the remaining life assessed, age alone is not a diagnosis, but a covering around 18 years or older warrants an assessment before anything is fastened through it.
Last updated . Data as of 23 August 2026.
Roof timing check
Remaining covering life against the array term.
— Verdict
— Remaining life
— Array term
— Covering age
A rule of thumb. Remaining life should come from a roofing professional.
HyreSolar does not inspect roofs, sell roofing or take a referral fee from roofers.
What each verdict means
Remaining covering life is the input that does the work, and it is not the same as age. A twelve-year-old roof in a harsh climate with poor ventilation may have less left than a twenty-year-old one in a mild one. Age is context. A roofer’s assessment is a diagnosis.
The comparison is deliberately crude because the decision is deliberately binary. Either the covering outlasts the array term or it does not, and if it does not you will pay to remove and reinstall. There is no partial credit.
This tool checks one thing and there are several others. It says nothing about deck condition, existing layers of covering, flashing detail, structural capacity or ventilation. Every one of those can change the answer, and none is visible from a date.
Replace the covering firstRemaining life is shorter than the array term. Doing both at once is one mobilisation instead of three, and the roofer can coordinate flashing with the mounting.
Covering can outlast the array termRemaining life meets or exceeds the term. Still confirm deck, flashing and penetrations on site before proceeding.
Age suggests a check firstYou have not entered a remaining-life figure and the covering is old enough that the question is real. Get an assessment rather than guessing in either direction.
How to use this calculator
Every input below is a number you can find, not one you have to guess. This is where each one comes from.
- 01
Enter the age of the covering
How long since the current covering was installed, not since the house was built. If the roof has been replaced, use the replacement date.
Where to find it Closing documents, a permit record with your building department, or the roofer’s invoice. A previous owner’s paperwork frequently survives in the house file.
- 02
Enter remaining life if you have an assessment
This is the input that produces a real verdict. Without it the tool falls back to age, which is much weaker.
Where to find it A roofing professional’s assessment. Ask specifically for remaining service life in years, not for whether the roof is "fine". Many will give you this as part of a free inspection.
- 03
Set the array term you are planning against
Twenty-five years is the conventional planning figure and matches most module warranties. Use your actual expectation if it differs.
Where to find it Your proposal’s warranty terms. Note that module warranties and workmanship warranties are different lengths, our workmanship warranty page explains why that gap matters.
- 04
Read the verdict as a prompt, not a permission
A pass here does not mean the roof is ready. It means this one comparison does not disqualify it.
Where to find it Follow up on deck condition, existing covering layers, flashing detail and ventilation with the roofer, not with this tool.
- 05
If the answer is replace first, sequence it deliberately
Doing both in one project is cheaper and produces a better flashing detail than doing them separately.
Where to find it Ask both contractors to coordinate. Our re-roofing page covers the sequencing and what to ask for in writing.
How this calculator works
Take the remaining covering life
From an assessment, in years. Age is a fallback, not a substitute.
Compare against the array term
Twenty-five years by default.
If remaining life is shorter, replace first
Because a removal and reinstallation is otherwise built into the plan whether or not anyone mentions it.
If no assessment was entered, fall back to age
A covering around 18 years or older prompts an assessment. Below that, the honest answer is that we do not know.
The formula, in full
If remaining life > 0 and remaining life < array term, replace the covering first. If remaining life ≥ array term, the covering can outlast it. If no remaining life was entered and age ≥ 18 years, get an assessment. Otherwise, inspect before deciding.
A worked example, start to finish
A ten-year-old asphalt covering, assessed by a roofer as having about fifteen years of service life left, against a system being planned on a conventional 25-year horizon.
Inputs
- Covering age
- 10 years
- Assessed remaining life
- 15 years
- Array term
- 25 years
- Shortfall
- 10 years
Result
Replace the covering first
The covering is expected to fail roughly ten years before the array does. Leaving it means a removal, a re-roof and a reinstallation somewhere around year 15, a cost that exists whether or not anyone puts it in the proposal. Replacing now makes it one project with one set of flashings.
How the answer moves
How the verdict changes. Every result is produced by the checker on this page.
| Covering age | Assessed remaining life | Array term | Verdict |
|---|---|---|---|
| 10 years | 15 years | 25 years | Replace the covering first |
| 5 years | 25 years | 25 years | Covering can outlast the array term |
| 8 years | 30 years | 25 years | Covering can outlast the array term |
| 20 years | not entered | 25 years | Age suggests a roof check first |
| 5 years | not entered | 25 years | Inspect before you decide |
The two not entered rows show what the tool does without an assessment: it escalates on age and otherwise declines to guess. Entering a real remaining-life figure is what turns this from a prompt into an answer.
What moves this number most
Ranked. A proposal can change any of these without saying anything untrue, so these are the inputs to check first.
The array term you plan against
Twenty-five years is conventional and matches most module warranties, but if you expect to replace the system sooner the comparison changes. Be honest about your actual horizon.
Covering age, but only as a fallback
It correlates with remaining life and does not determine it. Climate, ventilation, installation quality and material all move the real figure substantially in both directions.
What removal and reinstallation actually costs
The cost this decision turns on, and one we could not find a reliable published residential figure for. Ask your installer to quote it explicitly rather than assuming, and get it in writing before you decide to defer.
Everything this tool does not check
Deck condition, how many layers of covering are already up there, flashing detail, ventilation and structural capacity. Any of these can override a favourable verdict here.
Who warrants what afterwards
Fastening through a covering interacts with the roofing warranty, and the flashing is the component nobody backstops. See what happens when a roof leaks after installation.
Common mistakes with this calculation
Using age instead of an assessment
A twelve-year-old covering in a harsh climate can have less left than a twenty-year-old one in a mild one. Age is a prompt to ask; it is not the answer.
Assuming a covering with a 30-year warranty lasts 30 years
Material warranties describe manufacturing defects under stated conditions, not service life on your roof. Actual remaining life is a site assessment, not a label.
Deferring because the roof "looks fine"
Coverings fail from the deck up and from under the flashings, neither of which is visible from the ground. A pass on appearance is not a pass.
Not asking what removal and reinstallation would cost
It is the number the whole decision rests on. If nobody will quote it, you are being asked to defer a cost of unknown size.
Treating this as an inspection
It is one arithmetic comparison. It cannot see your deck, your flashing, your ventilation or how many layers are already up there, and it does not know what your local code allows.
Forgetting the warranty interaction
Penetrating a covering can affect the roofing warranty, and our research found the flashing is the component no manufacturer backstops. Establish who is responsible for a leak before anyone drills anything.
Naming the interest
The person best placed to answer this is not the person selling the array
The question "does this roof have twenty-five years left in it" has a technical answer. It also has a commercial context, and it is worth being blunt about that.
HyreSolar analysis. A solar salesperson who concludes that your covering needs replacing first has just delayed their own sale by several months and introduced a five-figure cost that competes directly with theirs for the same budget. That does not make them dishonest. It does mean the question is being asked of someone with a documented reason to prefer one answer, and that is worth knowing when you weigh the reply.
HyreSolar analysis. The converse holds too, and it is fairer to say so. A roofer asked whether your covering needs replacing has a commercial interest in saying yes. Neither trade is disinterested. The difference is that a roofing assessment produces a written condition report on a specific covering, which you can take to a second roofer, whereas a verbal "your roof looks fine" during a sales visit produces nothing you can check or carry.
The useful next step. Get a written condition assessment of the covering from someone whose business is roofs, before the array is designed. Ask specifically for estimated remaining service life in years, the basis for that estimate, and the condition of the flashings and penetrations. That document is what this calculator was built to take an input from — and it is the input people substitute a guess for.
HyreSolar analysis. HyreSolar has no stake in either answer. We do not install solar, do not roof, take no fee for an introduction to anyone who does either, and hold no list of approved contractors. That is precisely why this page is able to conclude "do the roof first and come back in three months", which is a conclusion nobody selling anything is incentivised to reach.
Illustrative chart with no data behind it. It exists to make the structural point visible, not to measure anything.
Why order matters more than timing
Getting the sequence wrong adds two whole jobs to the project
The cost of installing before re-roofing is not that the roof gets replaced. It is that the array has to come off and go back on, and that is a separate job nobody has priced.
HyreSolar analysis. Replace the covering first and the project is one roofing job followed by one solar installation. Install first and, when the covering fails, the project becomes a solar removal, a roofing job, and a solar reinstallation — three mobilisations instead of two, with the array off the roof and generating nothing in between, and a set of new penetrations that somebody has to warrant.
HyreSolar analysis. The removal and reinstallation is the part that surprises people, because it appears nowhere in the original proposal and is not a cost anybody quoted at the time of purchase. It is a real obligation created by a sequencing decision made years earlier, and by the time it arrives you have no leverage: the array is already on the roof, and the company that installed it may or may not still exist.
The useful next step. Ask, before signing the solar contract, what removal and reinstallation would cost and whether that figure is in writing anywhere. Ask whether the price is fixed, indexed, or "at prevailing rates" — those are three different answers. And ask who warrants the new penetrations afterwards, because a re-roof by a third party can affect what the original workmanship warranty covers. See what a workmanship warranty actually covers.
HyreSolar analysis. We do not publish what removal and reinstallation costs. HyreSolar does not install solar, does not lend, is not a utility, and holds no dataset of quotes, bids or completed installations. Nothing here is a price we have observed. That is also why these tools are free to tell you that the answer is to do nothing. What we can say is that it is a foreseeable expense which is routinely left out of a twenty-five-year savings model, and that asking for the number costs you nothing.
Illustrative chart. It counts mobilisations to make the sequencing point; it is not a cost comparison and must not be read as one.
Three documents, three parties
The three warranties that interact when an array sits on a covering
A roof with solar on it is covered by several overlapping promises made by different companies. The gaps between them are where the disputes happen.
| Warranty | Who gives it | What it covers | What its absence means |
|---|---|---|---|
| Roofing material warranty | The covering manufacturer. | Defects in the material itself, usually prorated and usually conditional on approved installation. | A term of years on a package is not a service life. Ask what it pays and under what conditions. |
| Roofing workmanship warranty | The roofing contractor. | The installation of the covering, including flashings and penetrations they made. | Nobody stands behind the labour. This is usually the shorter and more consequential of the two roofing warranties. |
| Solar workmanship warranty | The solar installer. | The mounting, the penetrations they made, and typically leaks attributable to them for a stated term. | A leak at a mount becomes an argument between two trades with you in the middle. See a leak after solar. |
| Module performance warranty | The module manufacturer. | Output as a percentage of nameplate at stated years. | The modelled degradation rate in the proposal is unbacked by anything contractual. |
| Inverter warranty | The inverter manufacturer. | The unit itself, for a term that is frequently shorter than the array’s design life. | Mid-life replacement is an unbudgeted cost. Ask for the term and what labour is included. |
Model-code and manufacturer terms vary; nothing here is legal advice. Read the actual documents for your own project rather than relying on a general table, including this one.
When the simple comparison breaks
Four situations this comparison does not handle well
The tool compares one remaining-life figure against one array term. Real roofs are less tidy than that.
Only part of the roof needs replacing
A covering does not age uniformly. A south-facing plane exposed to the most sun frequently has less life left than a shaded north face — and the south plane is also where the array wants to go.
The useful question becomes specific: what is the remaining life of the planes the array will occupy, rather than of the roof as a whole. Ask for the assessment plane by plane.
The covering is fine but the flashings are not
Penetrations, valleys and flashings frequently fail before the field of the covering does. An array does not care about the field; it adds mounts, and mounts are penetrations.
A condition report that addresses only the covering has answered half the question.
You are not sure how long you are staying
Both the array and the covering are long-lived assets whose value at sale is uncertain. If you expect to move within a few years, the sequencing question may be less important than the ownership question.
See buying a house with solar and what happens to a loan or lease at sale.
The array does not have to go on the roof
If the covering is near the end of its life and a re-roof is not affordable this year, the decision is not necessarily "wait" — it may be "put it somewhere else".
See ground mount versus roof mount and carports. Both avoid the interaction entirely.
Two trades, seven questions
What to ask the roofer, and what to ask the installer
Each of these has a written answer. Collecting them takes a fortnight and it is the cheapest part of the whole project.
- Roofer: what is the estimated remaining service life, plane by plane?
In years, with the basis stated. This is the input the calculator on this page actually wants, and the one most often replaced with a guess about age.
- Roofer: what condition are the flashings and penetrations in?
Separately from the field of the covering. It is frequently where a roof fails first and where an array adds the most new work.
- Roofer: would you re-roof under an existing array, and at what premium?
Some will not. Knowing that before the array goes up is worth a great deal more than discovering it in year nine.
- Installer: what does removal and reinstallation cost, in writing?
Fixed, indexed, or at prevailing rates — three different answers. Get the figure while you still have negotiating leverage.
- Installer: what does your workmanship warranty cover, and for how long?
Specifically leaks at your mounts. And ask what happens to it if a third party re-roofs under the array.
- Installer: has anyone assessed the structure for the added load?
A separate question from the covering, with a separate answer. See panel weight and roof loading.
- Either: "the roof looks fine" with nothing in writing
Not an assessment. It is an opinion offered during a sales visit, and you cannot take it to anybody else or rely on it later.
- A proposal that schedules installation before a re-roof you already know is due
This is the specific failure this page exists to prevent. If the covering is going to be replaced inside the array’s life, doing it first is almost always the cheaper order.
The real blind spots
What this checker cannot do
The roof-before-solar checker compares two numbers you supply. It has not seen your roof and it cannot see your roof.
It is not an inspection
It performs no assessment of any kind. It takes a remaining-life figure from you and compares it against a term you also supply.
If the remaining-life figure is a guess, the verdict is a guess with better formatting.
It cannot assess structure
Load-bearing capacity, rafter condition, snow and wind loading and any required reinforcement are outside it entirely.
That assessment requires somebody qualified to look at the building, and we give no guidance on doing it yourself.
It does not know the covering type
Different coverings age differently, fail differently and interact with mounting hardware differently. Some are considerably harder to work around than others.
A single "remaining years" input flattens all of that. The roofer’s report should not.
It prices nothing
HyreSolar does not install solar, does not lend, is not a utility, and holds no dataset of quotes, bids or completed installations. Nothing here is a price we have observed. That is also why these tools are free to tell you that the answer is to do nothing.
It cannot tell you what a re-roof costs, what removal and reinstallation costs, or whether doing both at once earns a discount. Those are quotes to obtain, not figures for us to invent.
It does not know your plans
A twenty-five-year comparison is only meaningful if you expect to be there, or expect the next owner to value what you built.
If you may move inside five years, the sequencing question is probably not the one to be solving first.
It cannot tell you to proceed
A favourable verdict here means one specific obstacle is absent. It says nothing about price, tariff, shading, installer or contract.
"The roof is fine and you still should not buy this system" is an entirely coherent position, and this page cannot reach it.
Important: this is a planning estimate
- A rule of thumb, not an inspection, and not a structural opinion.
- Does not assess deck condition, existing covering layers, flashing detail, ventilation or structural capacity.
- Remaining life should come from a roofing professional. Age alone is weak evidence.
- Does not know your local code, your covering material or your climate.
- HyreSolar does not inspect roofs and does not sell roofing.
Questions this calculator answers
Should I replace my roof before installing solar?
If the covering’s remaining service life is shorter than the array term, yes. A roof with fifteen years left under a twenty-five-year array means someone removes the array, re-roofs and reinstalls it around year fifteen. Doing both now is one mobilisation instead of three and produces a better flashing detail.
How old is too old for solar?
There is no age that settles it, which is why this tool asks for remaining life instead. That said, a covering around eighteen years or older warrants a professional assessment before anything is fastened through it. Below that, and without an assessment, the honest answer is that nobody knows yet.
How do I find out my roof’s remaining life?
Ask a roofing professional for an assessment and ask specifically for remaining service life in years, not for whether the roof is "fine". Many roofers provide this as part of a free inspection. Ask what they based the figure on, because a number with a reason behind it is worth much more than a number.
My roof has a 30-year warranty. Does that mean 30 years of life?
No. A material warranty covers manufacturing defects under stated conditions, usually with prorated terms and exclusions. It is not a promise of service life on your particular roof, where climate, ventilation, installation quality and slope all matter. Use an assessment, not the label.
What does it cost to remove and reinstall panels for a re-roof?
We could not find a reliable published residential figure and we will not invent one. It is the number this whole decision turns on, so ask your installer to quote it explicitly and get it in writing. If nobody will quote it, you are being asked to defer a cost of unknown size.
Can I install solar on an older roof anyway?
Usually you physically can, and the question is whether you should. The array does not damage a sound covering, but it does make the eventual re-roof more expensive and more complicated. If you intend to sell before the covering fails, that changes the calculation, though it also becomes a disclosure question.
Does this check whether my roof is strong enough?
No. This is a covering-life comparison and says nothing about structure. Our page on panel weight and roof loading covers what the code actually requires, including the finding that the widely quoted 4.5 pounds per square foot limit is an Oregon amendment rather than model code.
Will drilling into my roof void the roofing warranty?
It can, and it depends on the manufacturer and on who does the work. This is worth establishing in writing before anyone drills. Our page on roof leaks after installation covers who is responsible for what, and why the flashing is the component no manufacturer backstops.
What if I only need part of the roof replaced?
Then the comparison is about the plane the array will sit on, not the whole building. Enter the remaining life of that plane. A roof that is sound where the panels go and failing elsewhere is a different project from a whole-roof replacement.
Is there a way to avoid this decision entirely?
Yes: put the array somewhere other than the roof. A ground mount is designed as its own structure and takes the covering out of the question completely, though the fire code imposes a ten-foot brush-free perimeter and siting goes to municipal zoning. Our comparison page covers what that actually involves.
The research behind these numbers
Every assumption in this calculator is argued from primary sources somewhere in our research library. These are the pages that matter for this one.
- Should you re-roof before solar? The full version of this decision: sequencing, what to ask for in writing and what a combined project changes.
- When the roof leaks after installation Who is responsible, and why the flashing is the component nobody warrants.
- Panel weight and roof loading The 4.5 psf figure everyone quotes turns out to be an Oregon amendment rather than model code. What actually applies.
- The workmanship warranty What covers the penetrations, for how long, and what both major warranties exclude.
- Removing and reinstalling an array What the operation actually involves, and why we will not publish a residential cost figure for it.
- Ground mount versus roof mount The option that removes the roof from the question entirely.
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Written and audited by
HyreSolar Research
Primary-source research, data analysis and fact checking
We are a research desk, not a sales floor. We read the statute, the tariff, the code section, the federal filing or the manufacturer data sheet ourselves, and we publish the figure with the document it came from and the date we retrieved it. Where a number cannot be traced to a primary source, we publish the shorter page and say what we could not verify. That rule has cost us whole sections, and it is the reason the rest can be trusted.
- 160
- primary sources read and cited
- 220
- figures with a retrieval date
- 115
- federal and state government sources
- 66
- researched pages published
How this desk works
- Primary sources only. Statutes from the legislature’s own publishing system, federal data from the agency that collects it, code text from the adopted edition, manufacturer claims from the data sheet. We do not cite an article that cites a source; we go and read the source.
- Every figure carries its provenance. A named document and the date we retrieved it, so you can check it and so you know how old it is. Retrieval dates are not decoration: an EIA rate from May is a different fact from an EIA rate from August.
- We publish what we could not verify. Every research page carries a section naming the things we tried to establish and could not, and why. A paywalled standard, a state website that refused the request, a manufacturer that publishes no figure at all.
- We separate measurement from modelling from our own reasoning, and label which is which on the page. A laboratory measurement, an assumption inside a modelling tool and our own inference are three different kinds of claim and they are never presented as one.
- We do not sell solar, and we take no payment for placement, ranking or a favourable mention. Nobody buys a position on this site.
Data as of 23 August 2026. Authorship on this site is organisational: the analysis belongs to the desk rather than to a named individual, and we do not publish credentials we do not hold. Our editorial policy sets out how we source, date and correct what we publish.
Data and sources
- 2024 International Residential Code, rooftop photovoltaic provisions (ICC, retrieved 2026-09-03. Context for what the code requires of a rooftop array and its mounting.)
- Solar Photovoltaic Systems in Building Codes (ICC, retrieved 2026-09-03. Read alongside the above for the surrounding requirements.)