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The Roof Started Leaking After The Panels Went On
Damp on a bedroom ceiling or a stain in the loft that was not there before the array was installed.
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What's happening?
An on-roof array is held by brackets that pass through the roof covering to the rafters, so every mounting point is a deliberate penetration that has to be sealed by lifting and reforming the covering around it, not by squeezing sealant over a hole. On a tiled roof the correct method uses a hook that sits under a tile with the tile relaid over it; on slate it means dressing lead or a proprietary flashing. Where a leak appears after installation, it is nearly always one of four things: a cracked tile that was walked on and never replaced, a bracket bedded straight through a covering that was not reformed over it, a penetration for the DC cable entry that was sealed rather than flashed, or a gutter blocked by debris knocked down during the install so water backs up under the eaves. The important detail is timing — a leak that appears in the first wet season after an installation is evidence, and it is worth documenting before anyone repairs it.
What usually causes it?
- Tiles or slates cracked underfoot during installation and left in place
- Mounting brackets fitted without correctly relaying the covering over the hook
- The DC cable entry sealed with mastic instead of a proper flashing or tile
- Fixings into battens rather than rafters, letting the array move and work the covering loose
- Gutters or valleys blocked with debris dislodged during the install
- An already-tired roof covering disturbed by the work, so an old weakness finally lets go
- Condensation in the loft mistaken for a leak after a cable entry disturbed the ventilation path
Is it dangerous?
Water and electricity are together in the loft here, and that is why this one is rated high. Water tracking along DC cabling, into an inverter mounted in the loft, or onto a junction box is a fire and shock risk, not just a decorating problem. If water is running near the inverter or any electrical enclosure, isolate the AC side and get it looked at urgently. Persistent leaks also rot rafters and battens, which is what turns a cheap repair into a re-roof.
Can I fix it myself?
Document, do not climb. Photograph the stain with a date, note whether it appears only in driving rain from one direction, and put a container under an active drip. From a window or with binoculars from the garden, look for an obviously slipped or cracked tile near the array and for a gutter overflowing below it. Find your installation paperwork and the workmanship warranty — an installation carried out by a certified installer under a consumer code carries obligations, and the first call should be to the firm that did the work.
When should you call a solar installer?
Call the original installer first and in writing, because a leak traced to their fixings is their defect to put right. Call a solar installer or a roofer urgently if water is anywhere near electrical equipment. Where the original firm has ceased trading, the consumer code or workmanship warranty that backed the installation is the route — the certification and code bodies both operate complaints processes.
What will the solar installer actually do?
- Inspect the array's mounting points, flashings and cable entry from the roof
- Trace the leak path in the loft back to a specific penetration or a broken covering
- Lift panels where necessary to replace cracked tiles and reform the covering around brackets
- Reflash the DC cable entry properly where it was sealed with mastic
- Clear gutters and valleys of installation debris and check the array's drainage path
- Check DC cabling, junctions and any loft-mounted inverter for water damage before re-energising
Frequently asked questions
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