How to Clean a Conservatory Roof and Keep It Looking Like New

A conservatory roof gets the worst of the weather. Leaves, moss, bird mess, pollen and grime from rain all build up over time, dulling the glass and blocking light. A good clean once or twice a year keeps the room bright and stops dirt working its way into seals and gutters.

Here's how we'd tackle it: the tools to use, the order to work in, and the bits most homeowners get wrong.

How often should you clean a conservatory roof?

Most conservatory roofs need cleaning twice a year. Once in spring after the worst of the winter weather, and once in autumn when the leaves have come down. Properties near trees or busy roads need it more often. Leave it longer than a year and moss bonds to the glass, making the job much harder.

In Reading and across the rest of Berkshire, our wet autumns and damp springs are the main drivers of green algae on north-facing roofs. If you can see a green tinge from inside, it's time.

What you'll need to clean a conservatory roof

You don't need anything specialist. A trip to a local DIY shop will sort you out. Here's a kit list that covers every type of conservatory roof we come across:

• A telescopic cleaning pole long enough to reach the ridge (most extend to 4-6 metres)

• A soft-bristle brush head for general dirt and a slightly stiffer one for moss

• A microfibre washing pad or T-bar washer

• A squeegee head for finishing

• A bucket of warm water

• A small amount of mild washing-up liquid, or a dedicated conservatory cleaner

• A garden hose, ideally with a spray attachment

• A sturdy ladder and someone to foot it

• A pair of non-slip shoes if the ground is wet

Avoid abrasive scourers, wire brushes, or any cleaner containing bleach, ammonia, or solvents. Polycarbonate scratches easily, and harsh chemicals can damage rubber seals and the coating on self-cleaning glass.

How to clean a glass conservatory roof

Glass roofs are the easiest to clean and the easiest to damage if you go in too hard. Stick to soft brushes, plenty of water, and the lightest touch needed to lift dirt.

1. Clear loose debris first. Use a soft brush on the end of your telescopic pole to sweep leaves, twigs and grit off the surface and out of the gutters. Skipping this step grinds dirt into the glass once you start washing.

2. Rinse the roof with a hose. Start at the ridge and work down towards the gutter. Let gravity do the moving for you. Don't use a pressure washer. The force can drive water past seals and into the conservatory.

3. Wash with mild soapy water. Mix a few drops of washing-up liquid into warm water. Wet the brush head, work in sections from top to bottom, and don't let the solution dry on hot panels or you'll get streaks.

4. Tackle stubborn marks. For moss or algae, switch to the stiffer brush and use slow, controlled strokes. Sap, bird mess or tar usually shifts after a few minutes of soaking before scrubbing.

5. Rinse thoroughly. A second pass with the hose lifts any detergent residue, which will leave streaks if left to dry.

6. Finish with a squeegee. Pull from the ridge down to the gutter in single passes. Wipe the blade between strokes so you're not just spreading water around.

Pick a cloudy, dry day if you can. Direct sun dries the glass too fast and leaves marks.

How to clean a polycarbonate conservatory roof

Polycarbonate is more forgiving than glass in some ways and less in others. It picks up scratches easily, so the rules around soft brushes and gentle cleaners matter even more. The process is otherwise the same: clear debris, rinse, wash with mild soapy water, rinse, and finish with a squeegee.

Two extra things to watch with polycarbonate:

• Algae loves to grow inside the flutes of twin-wall polycarbonate sheets, where you can't reach it. If you've got green inside the sheets, no amount of cleaning the outside will fix it. The roof has reached the end of its useful life.

• End caps and breather tape keep moisture and dust out of the flutes. If these are damaged or missing, the panels will dirty from the inside no matter how often you clean them.

Cleaning the inside of the conservatory roof

The underside builds up dust, condensation marks and the odd cobweb too. A microfibre cloth on a long extending duster, used dry first and then very lightly damp, will sort most of it.

While you're up there, check the rubber seals around any rooflights, vents or roof bars. Perished seals are one of the most common reasons a conservatory starts to leak, and they're much easier to spot from the inside than the outside.

Staying safe when cleaning a conservatory roof

We have to mention this one because we've seen too many people take risks they didn't need to. The Health and Safety Executive publishes detailed guidance on working at height for good reason: a conservatory roof is no different to any other roof when it comes to falling off it.

A few rules we work by, and would suggest you do too:

• Never stand on a conservatory roof. Glass panels and polycarbonate sheets are not designed to take weight and will give way.

• Use a telescopic pole from the ground wherever possible.

• If you must use a ladder, set it on level ground, ideally on a ladder mat, and have someone foot it.

• Don't lean across the ridge to reach the far side. Get down and move the ladder.

• Wait for a dry, still day. Wet panels and gutters are slippery, and windy weather makes ladder work risky.

If your conservatory is two storeys high, sits against a sloped section, or you're not confident on a ladder, call a window cleaner or a professional conservatory cleaning service. The job isn't worth a hospital trip.

When a clean isn't going to fix the problem

There comes a point where no amount of scrubbing will bring a conservatory roof back. We replace conservatory roofs across Berkshire, so we see plenty of roofs that have been cleaned over the years, and plenty that haven't. The signs that a clean won't help:

• Algae growing inside polycarbonate flutes that no cleaner can reach

• Yellowing or cloudy polycarbonate that won't come clean

• Glass panels with permanent water marks from failed seals

• Roof bars showing rust, splits or sealant failure

• A room that's freezing in winter and boiling in summer regardless of how clean the roof is

Cleaning helps with appearance. It won't fix a roof that's past its lifespan, and it won't make a glass or polycarbonate conservatory comfortable to use all year. If your conservatory falls into that camp, a solid warm roof replacement is usually the better answer. We've written more about how the replacement process works if you want the detail.

Want an honest opinion on your conservatory roof?

If you've cleaned the roof and the room still isn't comfortable, or you've spotted any of the warning signs above, we're happy to take a look. We're a family-run firm based in Reading and we can replace a conservatory roof in Caversham, Woodley, Wokingham, Newbury or anywhere else nearby.