How to make sure solar panels don’t cause roof leaks
The big worry when looking at solar panels is: will they make your roof leak? The simple answer is they won’t, providing workmanship is correct. In cases with professional installation, the roof can actually be more watertight than before. Getting it wrong means poor flashing and sealing of the mounting points. Knowing this points you in the right direction, shows you who to hold accountable, and how to pick a good installer.
Let’s see how solar panels should be installed right.
- Panels don’t cause leaks; bad installation does. A properly fitted system keeps the roof as watertight as before, or more so.
- Leaks come from the mounting points. The penetrations where brackets pass through the roof must be flashed, not just sealed.
- Panels can protect the roof. By shielding the covering from sun, rain and hail, they can extend its life.
- Never fit on a failing roof. If the roof is old or worn, re-roof first; adding panels can be the last straw.
- A leak is the installer’s responsibility. It falls under their workmanship warranty, not the panel warranty or, usually, insurance.
Do panels cause leaks?
The panels themselves don’t. They shed rain and sit above the covering; what creates the potential for a leak is how the system is fixed to the roof. Most on-roof systems attach to the rafters with hooks or brackets that pass through the roof covering, and each of those is a penetration that has to be made watertight.
Done properly, that’s a solved problem. A good installer treats every mounting point like a chimney or vent pipe, weatherproofing it with proper flashing, a shaped barrier that channels water away, rather than a blob of sealant. The leaks that do occur are the mark of a poor install, not a flaw in solar itself.
- Roof penetration
- Any point where a fixing passes through the roof covering. Each one must be weatherproofed.
- Flashing
- A shaped physical barrier that channels water away from a penetration. The proper fix, as opposed to sealant alone.
- Roof hook / bracket
- The hardware that fixes the array to the rafters, passing between or through the tiles. Each roof type needs its own.
- Ballasted / non-penetrating mount
- A weighted racking system, used mainly on flat roofs, that holds panels down without drilling through the roof.
- Workmanship warranty
- The installer’s guarantee of the quality of the installation, including leaks caused by their work.
Where leaks actually come from
A leak under an array almost always traces to the fixing points, not the panels. These are the usual culprits.
| Cause | What goes wrong |
|---|---|
| Poorly flashed penetrations | Relying on sealant alone, or rushing it; by far the most common cause |
| Wrong mounting hardware | Kit not matched to the roof type: slate, concrete tile, clay or flat |
| Cracked tiles or slates | Covering damaged during the install and left unsealed |
| Missing the rafter | Bolts driven into the decking rather than the timber, and not sealed |
| Too few or wrong fixings | Not fitted to the manufacturer’s specification for the roof and slope |
| Pre-existing roof problems | An old or worn roof the install revealed, or tipped over the edge |
Not every leak that appears after an installation was caused by it. Old roofs often have hairline cracks, degraded flashing around chimneys or worn mortar, and the solar work may simply be the first time in years anyone climbed up and looked closely. That doesn’t let a bad install off the hook, but it’s why a proper roof survey beforehand matters so much.
Can panels protect the roof?
Here’s the counterintuitive part. Far from harming your roof, a well-installed array can help preserve it. The panels shield the tiles or slates beneath from UV, driving rain and hail, the very things that weather a roof over decades, so the section under the array ages more slowly.
That only holds on a sound roof, which is the one big timing caveat. No reputable installer will fit panels on a roof in poor condition: adding an array to a failing roof can be the straw that breaks the camel’s back, and removing and refitting the panels when the roof finally has to be replaced is an expensive job. If your roof is old or near the end of its life, re-roof first, then install.
Whose fault, and who pays?
If a leak does appear, responsibility is usually clear, though it catches people out because it doesn’t sit where they expect.
| The problem | Who’s responsible |
|---|---|
| A leak from the installation | The installer, under their workmanship warranty |
| A faulty panel or inverter | The manufacturer, under the product warranty (not leaks) |
| Resulting water damage inside the home | Buildings insurance may cover it, not the install flaw itself |
| Installer has ceased trading | An Insurance-Backed Guarantee, or an independent repair |
The trap is that many solar warranties cover only the panels and inverter, not the roof beneath them, so a “25-year warranty” may say nothing about leaks. It’s the installer’s workmanship warranty that has to cover the roof. For the full picture on warranties and your legal rights, see our guides to solar panel warranty claims and consumer rights for solar installations.
If your roof leaks
Act promptly; a small leak does disproportionate damage if left. The signs are damp patches or water stains on ceilings, dampness or a musty smell in the loft after heavy rain, and discolouration near where the panels are mounted. If you see them, work through it in order.
Photograph and film the leak point, any water damage and the date it started, from the ground or the loft, not the roof. A warranty claim turns on this evidence.
If the leak started after installation, the installer is the first port of call under their workmanship warranty, and a reputable one will put it right at no cost.
If the installer is unresponsive or disputes it, make a formal complaint and escalate it to their consumer code (RECC or HIES) or to MCS, which now handles complaints about its installers directly. If they’ve ceased trading, claim on the Insurance-Backed Guarantee.
The leak sits under the array, so fixing it means lifting the affected panels, repairing and re-flashing the roof, then refitting. It’s rarely fixable without removal.
Don’t climb up to inspect or patch a leak yourself. It’s dangerous, the panels stay electrically live in daylight, and a DIY fix over cracked flashing rarely lasts. Leave the repair to a qualified installer or roofer who can lift the panels safely.
How to prevent it
Almost every leak is avoidable, and prevention happens before the panels go up, not after.
- Use an MCS-certified installer with a strong track record.
- Insist on a pre-installation roof survey covering the structure, the tile or slate type, the pitch and any existing damage.
- Ask exactly how penetrations will be sealed, and insist on proper flashing for each one, not sealant alone.
- Confirm the mounting hardware is the correct kit for your roof covering.
- Sort a tired roof first. Re-roof before installing, never on top of a failing roof.
- Get a workmanship warranty that covers the roof, not just the panels, for well beyond the two-year MCS minimum, and keep the paperwork.
Frequently asked questions
Do solar panels cause roof leaks?
Not in themselves. A properly installed system stays watertight because the mounting penetrations are flashed and sealed like any other. Leaks come from poor installation, chiefly badly sealed penetrations, not from the panels.
Why is my roof leaking after solar panels were fitted?
Usually because a mounting penetration wasn’t flashed properly, a tile was cracked or the wrong hardware was used, all workmanship issues. Occasionally the roof had a pre-existing fault the install revealed. Either way, contact your installer first under their workmanship warranty.
Who pays to fix a leak caused by a solar installation?
The installer, under their workmanship warranty. The panel manufacturer’s warranty doesn’t cover it, and buildings insurance usually covers the resulting interior damage rather than the faulty install itself. Check the workmanship warranty covers the roof, not just the panels.
Can solar panels protect my roof?
Yes, on a sound roof. By shielding the covering beneath from UV, rain and hail, a well-installed array can slow the roof’s ageing and extend its life. Panels should never be fitted to a roof in poor condition.
Should I replace my roof before installing solar?
If it’s old or worn, yes. Installing on a failing roof risks leaks and means paying to remove and refit the whole array when the roof is replaced. A reputable installer will survey the roof first and advise re-roofing before fitting if needed.
It’s the fitter, not the panels
Solar panels don’t cause roof leaks. A properly installed system leaves your roof as watertight as before and can even shelter the covering beneath. The leaks that do happen come from the mounting penetrations, and whether they were flashed and sealed to a proper standard.
Use an MCS-certified installer, insist on a roof survey and proper flashing at every penetration, and never fit panels on a roof that should be replaced first. Get those right and the risk is very small.
If a leak does appear, it’s the installer’s responsibility under their workmanship warranty. Document it, contact them first, and keep the paperwork that proves the work was theirs.
SOURCES: MCS standards MIS 3002 (The Solar PV Installation Standard) and MCS 012 (The Solar Mounting (Product) Standard), under which mounting kits are tested for weathertightness, wind uplift and fire; MCS financial-protection rules (a minimum two-year, transferable, insurance-backed workmanship guarantee on domestic installations); the Consumer Rights Act 2015; standard buildings-insurance exclusions for faulty workmanship. General information, not exhaustive.
DISCLAIMER: This guide is general information, not roofing, legal or insurance advice. Don’t attempt roof access or repairs yourself; solar panels stay live in daylight. Use a qualified, MCS-certified installer for fitting and any leak repair, and confirm warranty and cover details with your installer and insurer.
UPDATED: 19 October 2026.
