Roof Leaking After Solar Panel Installation? What to Do

Roof Leaks After Solar: Rare, But Fixable

A properly installed solar system should never cause a roof leak. With an MCS certified installer using the correct mounting hardware and weatherproof flashing, your roof is sealed as well (or better) than it was before. But leaks do happen — usually when corners are cut during installation or when pre-existing roof issues go unnoticed.

If your roof is leaking after a solar panel installation, here is what to check and what to do about it.

Common Causes of Post-Installation Leaks

• Poor sealing around roof hooks — Solar panels mount to the rafters via roof hooks that pass between tiles. Each penetration point needs proper flashing or sealant. If this is rushed or done with cheap materials, water finds a way in
• Cracked or displaced tiles — Walking on a roof during installation can crack tiles, especially on older properties. A cracked tile under a panel is hard to spot once the system is in place
• Pre-existing roof issues — Some roofs already have hairline cracks, degraded flashing around chimneys, or worn mortar. The installation may not have caused the leak — it may have just been the first time someone looked closely at the roof
• Incorrect mounting system — Different roof types (slate, concrete tile, clay tile, flat roof) need different mounting hardware. Using the wrong system for your roof type increases leak risk

What to Do If You Spot a Leak

• Document everything — Take photos and video of the leak point, any water damage, and the date it started. This evidence is important for warranty claims
• Contact your installer first — If the leak started after installation, your installer is responsible under their workmanship warranty. MCS certified installers carry insurance and are required to rectify defects
• Check your MCS certificate — This confirms the installer is registered and gives you a route to escalate if they are unresponsive. MCS has a complaints procedure and an insurance-backed guarantee scheme
• Get an independent assessment if needed — If your installer disputes responsibility, a roofing surveyor can determine whether the leak was caused by the installation or a pre-existing issue
• Do not attempt to remove panels yourself — Solar panels carry live DC voltage in daylight. Only qualified installers should work on them

Who Is Responsible?

If the leak is caused by the installation, your installer should fix it at no cost. MCS certification requires installers to:

• Carry public liability insurance
• Provide a workmanship warranty (typically 5-10 years)
• Participate in an insurance-backed guarantee scheme — so if the company closes, you are still covered

If the leak is due to a pre-existing roof problem, it falls outside the installer's warranty. However, a good installer should have flagged any obvious roof issues during the pre-installation survey.

How to Prevent Leaks in the First Place

• Choose an MCS certified installer — This is not optional. MCS certification means the company has been audited for quality, uses approved methods, and is insured. Check their certification at mcscertified.com
• Get a roof survey before installation — Any reputable installer will inspect your roof condition before quoting. If tiles need replacing or flashing needs repair, it should be done before panels go on
• Ask about the mounting system — Good installers use branded mounting systems (K2, Schletter, Van der Valk) with proper flashing kits. Ask what system they plan to use and why
• Check reviews — Look for installers with a strong track record. Five-star reviews from local homeowners in Milton Keynes and Buckinghamshire are worth more than flashy websites

What to Do Now

If you are dealing with a leak after installation, contact your installer immediately and reference your MCS certificate. If you are planning a new installation, use our free solar calculator to get a quote from an MCS certified local installer who surveys every roof before work begins.

Frequently Asked Questions