Never walk on a conservatory roof
Before we start — please, never, ever walk on a conservatory roof. I’m not being dramatic. Polycarbonate and glass panels are not designed to take weight. People have been seriously hurt falling through them.
The good news is you don’t need to walk on it. Modern window cleaning kit lets you clean a conservatory roof beautifully from the ground.
Why conservatory roofs get dirty so fast
They’re the dirtiest bit of most houses, and for good reason:
Sloped glass catches everything. Dirt that would run off a vertical window sticks to a sloped one. Algae, moss, leaves, pollen — they all collect.
No self-cleaning. Rain runs off too quickly to wash a sloped roof properly. It just shifts the dirt around.
Overhanging trees. Most conservatories sit at the back of the house near the garden, which often means branches and bird activity directly above. Sap, droppings and leaf matter all land on the roof.
Moss gets a foothold. Once moss establishes in the seams between panels, it spreads quickly and blocks drainage channels.
If you never clean your conservatory roof, within a couple of years it’ll go from bright and airy to murky and dark. Your whole room feels different.
The right kit
A soft conservatory brush on a telescopic pole. This is the main tool. Look for a flagged bristle brush specifically sold for conservatory roofs — they’re much softer than general window brushes. Hard bristles can scratch polycarbonate.
A telescopic pole with a 30° angled adaptor. You need to be able to angle the brush so it runs flat along a sloped panel. Straight poles don’t work well on a conservatory roof.
A water source. Ideally a garden hose with a connector that fits onto the pole, or a small waterfed system. For lightly dirty roofs, a hand-pump sprayer of soapy water works.
A conservatory cleaning solution. A 10:1 water to soap solution is fine for regular maintenance. For stubborn green algae, a specialist conservatory cleaner works better and is safer than bleach (which can damage seals).
A bucket and rinse cloth for the frames. Some dirt comes down the sides and you’ll want to wipe it off after the main clean.
The method
1. Pick a dry, overcast day. Not full sun (dries too fast, leaves streaks) and not rain (you’ll be working in it). A cool cloudy day is perfect.
2. Clear any obvious debris first. Leaves sitting on the roof and in the gutters at the edge of the conservatory — get them off before you start washing. If you try to clean around them, you’ll just drag the mess all over the roof.
3. Pre-wet the glass. Use your hose or sprayer to rinse the panels and knock off loose dirt. Start at the apex and work down.
4. Apply cleaning solution. Dip your brush into a bucket of soapy water or use a waterfed pole with soap feed. Scrub gently in long strokes along the length of the panels. Don’t scrub up and down against the grain — you’ll force water under the seals.
5. Work panel by panel. Do one full panel from apex to gutter, rinse, then move to the next. Don’t try to wash the whole roof at once — the soap will dry and streak.
6. Rinse thoroughly. This is the most important step. Any soap residue left on the roof will attract dirt back within days. Rinse each panel really well, using pure water if you have it. Tap water leaves mineral spots when it dries.
7. Do the gutters and trims. Conservatories have integrated gutters along the bottom. While you’re there, clear them out. Use a small hand trowel or a gutter scoop on a pole.
Specific problems and how to deal with them
Green algae streaks. Apply a specialist algae treatment, leave for 10 to 15 minutes, then scrub and rinse. Don’t use chlorine bleach — it can damage the sealant between panels.
Moss between panels. Carefully scrape out with a plastic filler spatula on a pole. Don’t use anything metal. Then treat with a mild biocide to stop it coming back.
Bird droppings. Soak with warm soapy water for 5 minutes before scrubbing. Trying to scrub dried droppings off dry panels can scratch the surface.
Sap from overhanging trees. Sap is the worst. A dab of white spirit on a microfibre works better than soap. Rinse very thoroughly afterwards.
Scratches. If your roof already has scratches from previous cleaning, cleaning won’t bring them back. But stop scrubbing with hard brushes or metal tools so they don’t get worse.
How often?
For most conservatories in the UK:
- A light wash twice a year (spring and autumn).
- A deeper clean once a year, usually in spring.
- Clear the gutters and trims at the same time.
Houses with lots of overhanging trees or nearby bird feeders may need three or four visits a year.
What you should never do
- Walk on the roof.
- Use a pressure washer — the pressure forces water past the seals and causes leaks.
- Use chlorine bleach — damages seals and can discolour panels.
- Use metal tools — scratches polycarbonate permanently.
- Use green scourers — same problem as metal tools.
- Ignore it for years — the longer you leave it, the more likely you’ll need a professional deep clean.
A note on polycarbonate vs glass
If your conservatory has glass roof panels, you can be slightly firmer with the scrubbing — glass is tougher. If it’s polycarbonate (the twin-wall translucent sheet you see on older conservatories), be much more careful. Polycarbonate scratches if you look at it wrong.
The tools and method are essentially the same, just be gentler with polycarbonate.
When to get a professional
If the roof hasn’t been cleaned in 5+ years. The build-up will be stubborn and you’ll need a proper pure water system and a bit of experience.
If the gutters are completely blocked. Integrated conservatory gutters can be tricky to clear. Blocked ones cause leaks into the room.
If panels are cracked or loose. Cleaning a damaged roof makes things worse. Get a conservatory repair company out first.
If you can’t safely reach from the ground. If the roof is tall, adjacent to a higher building, or obstructed by other structures, please don’t improvise. Call someone who’s got the right access equipment.
Need a professional instead?
I’ve been cleaning conservatory roofs around Watford for years. Pure water system, soft brushes, proper technique — and your conservatory comes back looking like new. Give me a call or drop me a WhatsApp for a free quote.
