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Solar and your roof
Whether panels cause leaks, what happens when the roof needs replacing, and the timing decision that saves people thousands.
The short answer: properly installed panels don’t cause leaks, and the covered area of roof usually lasts longer because it’s shaded from sun and shielded from weather. The real issue isn’t leaking — it’s timing. Put panels on a roof with a few years left and you’ll pay thousands to take them off and put them back.
The timing decision
Panels last 25 to 30 years. Asphalt shingles last 20 to 30. If those clocks are out of step, you have a problem coming.
| Roof age | What to do |
|---|---|
| Under 10 years | Go ahead. The clocks are close enough. |
| 10–15 years | Get a roofer’s honest opinion on remaining life before committing. Not the solar company’s opinion. |
| 15–20 years | Replace the roof first. Almost always cheaper than removing and reinstalling later. |
| Over 20 years, or visibly worn | Roof first, no question. |
Taking an array off so a roof can be replaced, then putting it back, typically runs $2,000 to $5,000 depending on system size.
That’s money for nothing — you end up exactly where you started. Replacing a roof five years early costs less than that in most cases, and resets the clock so both last the rest of the system’s life.
Get a roofer to assess remaining life before you sign a solar contract. It costs little or nothing and it’s the single most valuable hour in this whole process.
Do panels cause leaks?
Properly installed, no. Poorly installed, absolutely — and it’s the most common serious installation failure.
Mounting requires bolting through the roof into the rafters. Each of those penetrations must be flashed and sealed correctly. Done right it’s as watertight as a plumbing vent, which is also a hole in your roof and doesn’t leak.
Done badly, leaks appear one to five years later, once sealant has aged.
What good practice looks like:
- Flashing, not just sealant. A metal flashing plate slid under the shingle above, so water is physically diverted. Sealant alone eventually fails.
- Mounted into rafters, not just decking
- A workmanship warranty that names roof penetrations — ask specifically whether leaks are covered and for how long. Ten years is a good sign.
On a metal standing-seam roof, clamps grip the seams and no holes are drilled at all. If you have that kind of roof, you have the best possible situation for solar.
Roof types
| Roof | How it goes |
|---|---|
| Asphalt shingle | Easiest and cheapest. Most US homes. |
| Standing seam metal | Best case. Clamps on, no penetrations, roof outlasts the panels. |
| Corrugated metal | Fine, though it does need penetrations. |
| Concrete or clay tile | Workable, more labor, tiles break. Expect to pay more. |
| Slate | Difficult and expensive. Slate cracks and is costly to match. |
| Wood shake | Hardest. Some installers decline it, and fire codes may complicate things. |
| Flat or low-slope | Fine. Ballasted or tilted frames, often without penetrating at all. |
Weight, and whether your roof can take it
A modern array adds roughly 2.5 to 4 pounds per square foot. Most roofs built to code handle that comfortably — it’s a fraction of what a snow load represents.
Your permit application will usually require a structural assessment anyway, so this gets checked by someone qualified. Older homes, or roofs with existing sag, may need reinforcement. That’s a cost, not a barrier.
What to sort out before signing
- How old is the roof, and what does a roofer say about remaining life?
- Does the workmanship warranty explicitly cover roof penetrations and leaks?
- How are penetrations flashed — ask them to describe the method
- What does removal and reinstallation cost if you replace the roof later? Get it in writing now, while they want your business
- Does installing solar affect your existing roof warranty? Sometimes it does
- Who repairs the roof if a leak appears — the solar company or a roofer?
Doing both together
If the roof needs replacing anyway, doing both at once is efficient. One trip, one set of scaffolding, and the panels go onto a brand new surface.
Some solar companies coordinate this, and some roofers work with solar installers regularly. Ask — it’s a common enough combination that most areas have someone who does it.