How Do You Clean a Conservatory Roof Safely?

Why you should not walk on it

Glass and polycarbonate conservatory roofs are not made to carry a person. Glazing bars span a long distance between supports, and panels can crack or give way without warning, which is one of the commonest ways people are hurt on roofs. Even a tiled roof can be steep, slippery with moss and covered in loose tiles. Cleaning from a ladder leaning on the glazing is equally risky, because the load goes onto the panels and the gutter. A telescopic pole with a brush head, a window-cleaning water-fed pole from the ground or a platform that stands on its own base are all safer ways.

Some roofs cannot be reached from the ground, and the honest answer is then to have it done by someone with the right access equipment. We do not recommend roof walking by amateurs, and nor does anyone who has worked on one.

Glass and polycarbonate

For glass, use warm water with a squirt of mild detergent and a soft brush or sponge. Work from the top down, from the ridge to the eaves, so dirty water runs over uncleaned glass. Rinse with plenty of clean water and, if you like, finish with a squeegee on the inside. Self-cleaning glass has a coating that breaks down dirt when it rains, but it still needs a gentle rinse now and then, as covered in our page on whether self-cleaning glass is worth it.

Polycarbonate is softer and scratches easily, and cleaning needs more gentleness. Use a soft cloth or sponge, never a scouring pad or a hard brush, and avoid solvents, white spirit and strong cleaning agents, which can craze the surface. Algae on the shaded side can be wiped off with warm soapy water. If the sheets have gone cloudy, yellowed or brittle, cleaning will not restore them, and our guide to how long a polycarbonate conservatory roof lasts explains why.

Tiled roofs and moss

A tiled conservatory roof does not need regular washing, but moss and lichen can build up, especially on shaded or north-facing slopes. Brush off loose moss gently from a safe position and apply a roof-safe moss treatment according to the label, letting it work and wash off with rain. Avoid pressure washing a tiled roof. It strips the surface from the tiles, forces water under the laps and into the membrane, and loosens the mortar or fixings. Our guide to tiled conservatory roofs covers how these roofs are built.

Keep an eye on the flashing at the house wall and the ridge, and call us if you see slipped tiles or lifted lead.

Gutters, seals and the frame

Dirty roofs are often a gutter problem. Leaves and moss in the gutter hold water against the frame and overflow onto the glass. Clear them by hand or with a gutter scoop, flush with a hose and make sure the downpipe runs freely. Wipe down the frame, the cappings and the seals with the same mild solution. Do not use oil, polish or silicone spray on rubber seals unless the maker says to, as some products make them swell or perish.

While you are cleaning, look for signs that need attention: cracked panels, perished seals, stains around the bars, mould at the wall plate or drips inside. Report them early. Small faults grow, and our page on leaking conservatory roofs shows how.

Tools and products worth having

A small kit does most of the job: a telescopic pole with a soft brush head, a bucket, a microfibre cloth, a squeegee for the inside face and a hose with a gentle spray nozzle. For stubborn marks on glass, a dedicated glass cleaner or a little white vinegar in warm water works. Check the label of any cleaner against the roof material. For tiles, buy a moss treatment that states it is safe for roofs and follow the dilution on the bottle. Wear eye protection, avoid cleaning in strong sun, since the soap dries on the glass and leaves streaks, and keep pets and children away from run-off.

How often to clean

Twice a year suits most roofs, in spring after the winter grime and in autumn before the leaves fall. A roof under trees or near a busy road may want more. A regular wash keeps light levels up, stops algae and moss from settling and lets you spot problems.

If you would rather someone else did the work, we can clean and inspect the roof with proper access, and take pictures of the seals and bars as we go, so you can see how they are ageing. The price is fixed in writing before we start. For everything else we do on these roofs, start from conservatory roof replacement in Basingstoke.