How is a conservatory roof cleaned?

A conservatory roof looks solid from inside, but it is not built to carry a person. Glazed panels, polycarbonate sheets and the thin aluminium or uPVC bars between them are all designed to keep the weather out, not to take weight. That is the starting point for every clean: nobody climbs onto it, and nobody leans a ladder against the glazing itself.

Access comes from somewhere solid instead. The main house wall or roof can offer a safe position, a ladder can be footed on the ground at the eaves, or a long-reach pole carries the brush from below. If none of those reaches the middle of a wide roof, a platform or tower is the answer, and that is the point at which a quote ought to say whether access equipment is included. Our roof cleaning scaffolding answer explains when it is needed and when it is not.

Glass tolerates more than polycarbonate. Glazed roofs are washed with a soft brush or cloth head and clean water, plus a mild cleaner where algae has built up. Polycarbonate is a plastic, and its surface scratches and clouds if rubbed with a stiff brush or sprayed with harsh solvents, so it gets the gentlest approach: low-pressure rinsing and a cleaner made for the material.

High-pressure jets are left out for both. Hard water driven at a seal can push past it, and a conservatory that was dry last week can start dripping inside. The aim is a clean surface with the sealing left exactly as it was fitted. Where tiles form part of the roof, as on a solid or part-tiled conservatory, those areas are treated like any other tiled slope, with the moss removed and the biocide (the moss-killing wash) applied from a safe position. Each material gets its own method on the same visit.

Most green growth on a conservatory does not sit in the middle of a panel. It gathers along the glazing bars, at the edge of the seals, in the valleys between roof sections and in the gutter channel at the eaves, where water lingers. These are also the places where a drip begins, so cleaning them properly is as useful as polishing the glass.

Debris is cleared out of the channels and the outlets so water can leave the roof freely. If a gutter on the conservatory overflows after rain, the cause is often a blockage rather than a fault, and our answer on a conservatory gutter overflowing sets out how to tell the difference. The inside face of the roof can be wiped at the same visit if you want the bars done as well, but mention it when you ask for the quote so it is allowed for.

Cleaning improves the look and clears the channels. It does not repair a seal that has perished, a panel that has cracked or a roof that is simply worn out. Polycarbonate conservatory roofs are commonly put at around 10 to 15 years of life in published guides, so an older roof that has yellowed or gone brittle may be past the point where a wash helps.

You get a plain verdict after the look: clean it, repair a leak, or replace the roof. Our guide to the polycarbonate roof lifespan explains what to expect, and if water is already coming in, a leaking conservatory roof needs diagnosing rather than washing. Replacing a roof with a solid one is a different job again, and a solid conservatory roof needs Building Regulations approval before the work starts.

A conservatory roof stays cleaner for longer when overhanging branches are cut back and the gutter is cleared in autumn. Glazing that is shaded by a tree or a north-facing wall greens up fastest, in the same way that shaded tiles gather moss on the main house, so the position of the building tells you how often to expect the job. Rinsing the panels after a spell of wet weather, before a heavy film builds up, keeps each clean light.

Some owners look at self-cleaning glass to cut down on the work, and our answer on self-cleaning conservatory glass sets out what the coating does and what it leaves to you. For a one-off clean, the price is written after a look at the roof and covers the whole job, and the roof cleaning and moss removal page covers the work on the main roof if you would like both done together on one visit.