Roof leaking after solar installation

Safety first. Water and electricity together are dangerous. If water is dripping near a light fitting, fan, switch, distribution board or the inverter, switch that circuit off at the DB if you can do so from a dry spot, and keep everyone away. Do not touch wet switches. If water has reached the inverter or a DC isolator, follow water in inverter after rain and call a qualified engineer. Do not go on the roof during rain or storms.

This page is about fixing an existing leak. If you are planning a new installation and want to prevent leaks from day one, read solar roof waterproofing instead.

What a solar panel roof leak means

A flat RCC roof keeps water out with a top layer: waterproofing coat, tiles, screed or a mud layer, laid to a slight slope towards the drains. Installing a solar frame touches that layer in three ways:

• Anchor bolts are drilled through it into the slab.
• Base plates, ballast and cable trays sit on it and can change where water flows.
• Cables pass through a wall or roof into the building.

Each is a possible water path. An unsealed hole lets water run down the bolt into the slab; a frame that blocks the slope makes water pond and find the nearest crack. By the next monsoon, that shows as seepage after solar on the ceiling below.

Sometimes the solar is not the cause at all: an old roof with tired waterproofing leaks with or without panels, and the newest change gets blamed. A good diagnosis settles which it is.

Quick-check table

Roof leaking after solar installation: safe owner checks

Do these on a dry day, from the roof surface only. Do not lift panels, open junction boxes or touch DC cables and connectors.

1. Map the damp patch. From inside, measure where the patch sits relative to walls, beams and the stair room. Draw a rough sketch.
2. Find the same spot on the roof. Mark it on your sketch, then note every base plate, cable entry, drain and tray within a few metres.
3. Check after the next rain. Once the rain has stopped and it is safe, look for water standing against base plates, behind frames or under cable trays. Photograph it.
4. Inspect each base plate. Look for cracked or missing sealant, a gap under the plate, bare drill holes, or rust streaks. Rust here can mean water has been sitting for a while; see solar structure rust.
5. Check the cable entry. Is there a proper gland, conduit bend or hood, or just a hole with cables pushed through?
6. Clear the drains. Remove leaves, dust and plastic from drains and spouts, keeping clear of cables.
7. Send everything to your installer: sketch, photos of the ceiling, roof photos and the dates it leaked.

Avoid quick fixes like smearing sealant over every bolt or laying plastic sheets under the panels. Sheets can blow into panels in wind, and industry guidance on roof penetrations treats sealant as a backup layer, not the whole answer.

Water leakage from solar structure bolts

The most common single cause is a base plate fixing. Typical faults are:

• the hole was drilled but not filled with resin or sealant before the bolt went in;
• dust was not blown out, so the anchor or resin did not bond;
• the plate sits flat on the roof in a drain path, so water stands on the joint;
• the nut and bolt head were never sealed after tightening;
• sealant has cracked after a few summers of heat cycling.

The fix is not just more sealant on top. The engineer removes or loosens the plate, cleans the hole and surface, re-injects or replaces the anchor, seals under the plate and over the bolt, and where water collects, raises the plate on a small sealed plinth so the joint sits above standing water. Our waterproofing guide shows the full sealing sequence.

What an engineer will check

An engineer works from the inside out and the outside in:

• Water path. Matching the damp patch to roof features, allowing for water that travels along the slab. On some jobs, a controlled water test of one section at a time helps confirm the source.
• Each fixing. Anchor type, resin fill, plate seal and bolt seal.
• Drainage. Whether the frame layout, plates, ballast or trays now block the roof's slope, and whether drains need moving or frames need re-routing.
• Cable entries. Adding a gland, hood or conduit with a drip loop so water drips off before the wall.
• Roof condition. Cracks, failed waterproofing, or an old mud layer that leaks regardless of the solar. If the slab itself is a concern, see roof load and structural checks.
• Sheet roofs. On sheds, whether fixings went through the sheet into sound purlins with sealing washers, or only into the sheet. See solar on tin and metal sheet roofs.
• Electrical safety. Whether water has reached cables, junction boxes, the DB or the inverter, and testing insulation before the system runs normally again.

If the roof needs full re-waterproofing, panels may have to be lifted section by section. An elevated structure leaves more of the roof open for this work than a low frame; see L2 vs L3 vs elevated solar structures.

How to prevent seepage after solar

• Fix existing roof problems before installation and record the roof's condition with photos.
• Fill, seal and plinth every anchor; seal over every bolt.
• Run base rails along the slope, keep plates out of drain lines and lift trays off the surface.
• Seal every cable entry with a proper gland or hood.
• Inspect plates, drains and entries before every monsoon and after major storms, using our solar maintenance checklist.
• Reseal fixings that show cracks or gaps as they age.

Who is responsible for the repair?

It depends on where the water comes from and what was agreed in writing. A leak at an installer's fixing is a workmanship question; a roof that was already failing is a waterproofing question. Recording the roof's condition at the survey protects both sides. Our solar warranty guide lists what to get in writing.

Solar Works Pakistan structures carry a 3-year structure warranty, and our 1-year service warranty applies under the applicable project terms. Once a complaint is registered, we target sending service personnel within 48 hours to begin diagnosis; repair time depends on the cause and the weather. See how after-sales service works.

We can also inspect leaks on systems installed by other companies across Punjab, as a chargeable service.

Frequently asked questions

Why is my roof leaking after solar panels were installed?

Usually because an anchor bolt or base plate was not sealed, a cable entry is open, or the frame is blocking the roof's drainage. Sometimes the roof was already failing and the leak is unrelated to the solar. Trace the source before sealing anything.

Do solar panels cause roof leaks?

Panels themselves do not. Leaks come from how the frame was fixed and how water drains around it. A properly sealed and laid-out installation should not leak.

How do I stop water leakage from solar structure bolts?

The bolt hole needs cleaning, refilling with resin or sealant, resealing under the plate and over the bolt, and often a small sealed plinth to lift the joint above standing water. Sealant on top alone rarely lasts.

Why is the damp patch not under the panels?

Water often travels along cracks or layers in the slab before it appears on the ceiling. The source can be a few metres away from the patch, so it has to be traced.

Should the panels be removed to fix a leak?

Not always. Many fixing leaks can be repaired with the panels in place. If the whole roof needs re-waterproofing, panels may need to be lifted in sections, which should be done by the installer with the system safely isolated.

Is seepage after solar dangerous?

It can be if water reaches wiring, switches, the DB or the inverter, and long-term seepage can rust the steel in the slab. Switch off affected circuits if safe and have it checked quickly.

Sources

1. SurgePV, "Roof penetration waterproofing for solar" (why mounts leak, water travelling away from the penetration, sealant as a secondary layer, inspection intervals)