Issues · 6 min read
Cleaning a Cobham roof that has solar panels — what changes
Solar panels shade the tiles beneath them and trap moss in a way bare roofs don't. Here is how we safely clean roofs with PV installed.
Why PV roofs need more frequent cleaning
Solar arrays shade every tile beneath them and channel rainwater in unnatural patterns — accelerating moss growth on the pitches around them. Panel output also drops 5–15% under biological soiling.
Our PV-safe protocol
Isolated DC before any work; biocide diluted 20% lower than standard to avoid any residue on panel glass; a deionised-water panel wash on the same visit for £6–£9 per panel.
What to avoid
Never let anyone walk directly on PV modules. Never allow high-pressure water anywhere near the panel frame — micro-cracks void the manufacturer performance warranty.
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