Can green inside polycarbonate panels be removed?

Not from outside. Growth inside the flutes is sealed within the panel, and on older roofs replacement is often the only real answer.

Will cleaning cause my conservatory to leak?

Correct low-pressure cleaning should not. If a seal or flashing has already failed, cleaning may reveal it, which is worth knowing about.

Do you clean the gutter around the conservatory?

Yes, along with the junction between the conservatory and the main roof, which is where most leaks originate.

How often should a conservatory roof be cleaned?

Once or twice a year, more often if it sits under trees or beneath a mossy main roof.

Conservatory Roof Cleaning Guide

A conservatory roof is the surface nobody can see properly and everybody notices from upstairs. Sitting almost flat, shaded by the house for part of the day and fed by whatever washes off the main roof above, it collects algae, moss and debris faster than any vertical surface. It is also fragile, poorly designed for walking on, and full of seals that a careless clean will disturb. Done properly the difference inside the room is remarkable: a green roof cuts a surprising amount of light. This guide covers how it should be approached.

Glass, polycarbonate and solid roofs

Glass panels are the most forgiving surface but the least forgiving structure, since the glazing bars and seals do the work. Polycarbonate is soft, scratches easily and often has algae growing inside the flutes where nothing external will reach it. Solid tiled conservatory roofs are effectively small roofs and are treated like one. Each needs a different expectation set before work starts.

This guide sits under our Window Cleaning work, covering 20-mile radius of Plymouth.

Nobody should be walking on it

Conservatory roofs are not designed to carry weight and the glazing bars will not save a person who slips. Correct practice is water-fed poles from the ground, or working from a suitable platform or ladder positioned off the structure. If anyone proposes to climb onto the roof or lean a ladder against a glazing bar, that is the point to stop the job.

Green in the glazing bars

The dark green line along each bar is where debris and moisture collect and it is the main thing that makes a conservatory roof look dirty from above. It needs brushing along the bar with a soft brush and detergent rather than blasting, then rinsing with pure water so nothing dries as a tidemark. This is the fiddly, time-consuming part and it is what separates a proper clean from a quick hose down.

Algae inside polycarbonate flutes

Once green growth is inside the hollow chambers of a polycarbonate panel, external cleaning cannot remove it. Some installers can flush panels, but on older roofs the honest answer is often that the panels are at the end of their life. It is worth knowing this before paying for a clean that will improve the frames and bars but leave the panels looking green.

Debris from the roof above

Most conservatory roofs sit under a main roof pitch, so they receive moss, grit and leaf fall constantly. Clearing that debris off, and out of the box gutter or lead flashing at the junction with the house, is as important as the glass. A blocked junction gutter is the most common source of leaks appearing inside a conservatory.

Frames, finials and the gutter round the edge

uPVC frames respond to soft brushing and mild detergent; abrasives dull them and make the next clean harder. The small gutter around the conservatory perimeter fills with the same debris as the main one and is usually far more neglected. Finials and crestings collect grime and are worth doing while the pole is out.

Avoiding leaks and pressure damage

Water forced up under a lap, past a seal or into a glazing bar will find its way inside, sometimes not until the next storm. That is why conservatory roofs are washed rather than pressure cleaned. If a roof already leaks, cleaning will show it up rather than cause it, but it is fair to flag existing problems before work rather than after.

How often and when

Once or twice a year suits most conservatories, ideally in spring after the worst of the debris has fallen and again in autumn if there are trees. Combining it with a gutter clear on the main roof makes sense, since the two problems feed each other. Between visits, clearing leaves off the roof with a soft brush on a pole makes a real difference.

Reader note: Conservatory and glass roof cleaning done properly

Conservatory owner with a green roof and grimy frames.

Glass, polycarbonate and solid roofs: Glass panels are the most forgiving surface but the least forgiving structure, since the glazing bars and seals do the work. Polycarbonate is soft, scratches easily and often has algae growing inside the flutes where nothing external will reach it. Solid tiled conservatory roofs are effectively small roofs and are treated like one. Each needs a different expectation set before work starts. Nobody should be walking on it: Conservatory roofs are not designed to carry weight and the glazing bars will not save a person who slips. Correct practice is water-fed poles from the ground, or working from a suitable platform or ladder positioned off the structure. If anyone proposes to climb onto the roof or lean a ladder against a glazing bar, that is the point to stop the job. Green in the glazing bars: The dark green line along each bar is where debris and moisture collect and it is the main thing that makes a conservatory roof look dirty from above. It needs brushing along the bar with a soft brush and detergent rather than blasting, then rinsing with pure water so nothing dries as a tidemark. This is the fiddly, time-consuming part and it is what separates a proper clean from a quick hose down. Algae inside polycarbonate flutes: Once green growth is inside the hollow chambers of a polycarbonate panel, external cleaning cannot remove it. Some installers can flush panels, but on older roofs the honest answer is often that the panels are at the end of their life. It is worth knowing this before paying for a clean that will improve the frames and bars but leave the panels looking green. Debris from the roof above: Most conservatory roofs sit under a main roof pitch, so they receive moss, grit and leaf fall constantly. Clearing that debris off, and out of the box gutter or lead flashing at the junction with the house, is as important as the glass. A blocked junction gutter is the most common source of leaks appearing inside a conservatory. Frames, finials and the gutter round the edge: uPVC frames respond to soft brushing and mild detergent; abrasives dull them and make the next clean harder. The small gutter around the conservatory perimeter fills with the same debris as the main one and is usually far more neglected. Finials and crestings collect grime and are worth doing while the pole is out. Avoiding leaks and pressure damage: Water forced up under a lap, past a seal or into a glazing bar will find its way inside, sometimes not until the next storm. That is why conservatory roofs are washed rather than pressure cleaned. If a roof already leaks, cleaning will show it up rather than cause it, but it is fair to flag existing problems before work rather than after. How often and when: Once or twice a year suits most conservatories, ideally in spring after the worst of the debris has fallen and again in autumn if there are trees. Combining it with a gutter clear on the main roof makes sense, since the two problems feed each other. Between visits, clearing leaves off the roof with a soft brush on a pole makes a real difference.

Questions we get on this

Can green inside polycarbonate panels be removed?: Not from outside. Growth inside the flutes is sealed within the panel, and on older roofs replacement is often the only real answer.
Will cleaning cause my conservatory to leak?: Correct low-pressure cleaning should not. If a seal or flashing has already failed, cleaning may reveal it, which is worth knowing about.
Do you clean the gutter around the conservatory?: Yes, along with the junction between the conservatory and the main roof, which is where most leaks originate.
How often should a conservatory roof be cleaned?: Once or twice a year, more often if it sits under trees or beneath a mossy main roof.

If this describes your situation

Send a photo of the roof from an upstairs window and we will quote the panels, bars and gutter together.

Send photos for a quote Window Cleaning Call 07830 242403

Conservatory and glass roof cleaning done properly