Moss and Lichen on Solar Panels

Where growth starts

Moss usually begins on the surrounding tiles and on the aluminium frame, especially along the bottom edge where water and dirt collect. Shallow-pitched or shaded panels stay damp longer, giving moss and algae a foothold on the glass edge itself.

Lichen is slower growing and forms flat, crusty patches. It often appears on panels that have been in place for many years on damp or north-facing roofs.

Why it matters

Growth along the bottom edge can shade the lowest cells and hold water against the frame seals. Moss beneath panels can choke the gap between panel and roof, trapping leaves and creating a sheltered spot where birds may nest.

Moss washing off the roof can also block gutters below the array, causing overflow.

Removing moss and lichen gently

Glass coatings and frame seals are easily damaged, so scraping with metal tools or blasting with high pressure is not appropriate. Moss is eased away by hand with soft tools, and the glass is cleaned with a gentle, low-pressure method.

Lichen bonds tightly and can need patience. A suitable treatment may be considered where it is compatible with the panels; we confirm this when we see the system.

Dealing with the roof as well

There is little point cleaning the panels if the tiles around them are thick with moss. Hand moss removal from the surrounding roof, followed by a soft wash and biocide where suitable, reduces the source. See our solar panels and roof moss guide for how we work around arrays.

We never pressure wash roof tiles, with or without panels.

Checking underneath

When moss is cleared from the edges, it becomes possible to see whether debris, leaves or nests have collected under the array. If birds are using the gap, mesh proofing may be worth considering; our pigeons under solar panels guide explains why.

Wild birds and active nests are protected, so any proofing is timed and carried out with that in mind.

Keeping growth away

Trimming overhanging branches, keeping gutters clear so water drains away, and looking at the panels from the ground each season helps you catch growth early. A light, regular clean is easier than removing years of build-up.

Our cleaning frequency guide gives a sensible approach.

Panels near trees

Overhanging branches drop leaves and debris onto panels and shade them, keeping the surface damp. Moss and algae follow. Trimming branches back improves light and helps panels dry after rain.

Tree work should be done by a qualified tree surgeon, and some trees are protected by preservation orders or conservation area rules. Check with your council before cutting.

What happens if moss is left

Moss along the frame holds water against seals and corners, and can creep further across the glass each year. It also traps leaves and dirt, building into a strip that shades the bottom cells. Underneath the array, moss and debris can block the airflow that helps panels stay cool.

Dealing with growth early is much easier than removing years of build-up.

Older panels

Panels that have been on a roof for many years may have frames with more grime in the corners and seals that are past their best. They need an especially gentle approach. If we see damaged seals or cracked glass, we stop and tell you rather than cleaning over it.

Damaged panels should be looked at by your installer.

Gutters below the array

Moss scraped or washed from panel frames and tiles has to go somewhere, and much of it ends up in the gutter. Clearing gutters at the end of the visit stops that debris blocking outlets in the next downpour.

Our gutter cleaning service is often booked alongside panel and roof work for exactly this reason.

Getting a quote

Send photos of the panels and surrounding roof. Our solar panel cleaning and moss removal services can be combined, and quotes are free.