The short answer
A conservatory roof is cleaned gently and from a safe position, never by walking on it. Glass and polycarbonate scratch and can crack under a person's weight, and a harsh jet can force water past the seals. Use soft brushes, plenty of clean water and a mild cleaner. Cleaning is also the best chance to spot cracked panels, failed seals and clogged gutters.
Glass and polycarbonate need different care
Conservatory roofs are glazed in glass or in twin-wall polycarbonate, a plastic sheet with hollow channels inside. They look alike from the garden and behave differently under a brush.
Glass is hard but brittle. It takes a soft brush and a mild cleaner well and does not scratch easily from careful washing. It can crack from impact and point loads, so a stiff or gritty brush dragged across it is a bad idea.
Polycarbonate is softer. Its surface scratches, and abrasive cleaners, scourers or stiff bristles leave fine marks that catch dirt. The hollow channels inside can fill with water or dirt if the end seals are damaged, and the panel then clouds.
For both, the safe approach is gentle: clean water, a soft brush or cloth on a pole, and a mild washing-up-type cleaner. Rinse well so no film remains. Avoid solvents and anything labelled abrasive.
Treatments for algae and moss on the frame and gutters follow the same rules as elsewhere. HSE guidance rules out householders using biocides made for professionals alone, and runoff needs keeping off plants and away from drains.
The lifespans are modest. For polycarbonate, HomeBuilding says 10 years is typical and The Eco Experts about 10 to 15, so an old roof may be near its end whatever the cleaning.
Do not walk on it
The most important rule is simple: conservatory glazing is not made to carry a person. Glass and polycarbonate panels can break without warning, and a fall through one can cause serious injury. Fragile roofs are a recognised hazard, and the HSE has guidance on working at height worth reading before anyone goes up.
Never stand or kneel on the panels, and do not lean a ladder against them. Crawl boards laid across the roof are sometimes used by professionals, but they are no excuse for amateurs to try it.
The roof is usually cleaned from outside by someone standing on a ladder, tower or platform at the edge, using a long-reach brush or a water-fed pole. The cleaner can reach most of the roof without touching it. From inside, a wipe of the underside removes condensation marks and dust.
A high or large conservatory may need a tower or scaffold to reach the ridge safely. That adds to the price, and it should be included in the quote.
To check the roof yourself, take a photograph from an upstairs window or from the ground with a zoom. Our page on roof cleaning access explains how reach and safety are planned.
Faults found while it is clean
A clean roof shows what the dirt was hiding. This is often the most valuable part of the visit.
Look for the following.
- Cracked or chipped glass, or polycarbonate that has crazed or yellowed.
- Cloudy or damp patches inside the twin-wall channels, which mean the end seals have failed.
- Perished or loose glazing bars, rubber seals or cappings, where water can get in.
- Gaps or poor sealing along the wall of the house, often a lead or flashing detail.
- Gutters blocked with moss and debris, so water spills onto the frame.
- Green growth in the joints, which holds water against the seals.
None of these is a reason to panic. Most are repairable. A resealed bar, a replacement panel or a refitted flashing may be all it takes.
Leaks at a conservatory roof are often caused by the junction with the house. Our conservatory roofs hub covers repair and replacement, and our page on cleaning a flat roof covers a neighbouring case.
If the roof is old and failing in several places, repair costs add up, and replacement may be better value. We say which, with the evidence.
What we do and what to expect
We start by looking at the roof, from outside and, if we can, from inside. You see photographs of the panels, seals, bars, gutters and the house junction, with a plain explanation.
Cleaning then follows the gentle method: soft brushing, clean water, a mild cleaner and no walking on the panels. Where the roof is high or hard to reach, the access is arranged and included in the price. Any treatment of the frame or gutters uses approved products to the label.
Faults we find are reported, with photographs. We recommend a repair where a repair will do, and we tell you honestly if the roof is nearing its end.
The price is a single written sum, and it follows a visit to the roof, since access and condition decide both.
Frequent small cleans cost less than one big rescue. Do not leave a conservatory roof until the green is thick, because the growth works into the seals and makes the job harder. The roof cleaning and moss removal hub explains the full service in Farnborough, Fleet and Camberley.
