The short answer
A polycarbonate conservatory roof commonly lasts somewhere between ten and twenty years, depending on the quality of the sheet, the aspect and how well it has been looked after. The sheet itself does not wear out all at once. The signs of age are yellowing, clouding, brittleness, algae between the walls of the sheet and leaks at the seals. Cheap, thin or poorly supported sheets age faster than thick, UV-protected ones, and a good frame matters as much as the sheet.
What decides how long it lasts
Polycarbonate is a tough plastic, but sunlight attacks it. Better sheets carry a UV-protective layer on the outer face, which slows the breakdown. Cheaper sheets, or sheets fitted with the protected face turned inwards by mistake, yellow and turn brittle much sooner. Thickness matters too: 10 mm sheet is flimsy and flexes under snow, while 25 mm or 35 mm multi-wall is stiffer and better insulated, and lasts longer.
Aspect and exposure also play a part. A south-facing roof takes the most sun, so it ages quickest in strength, but it dries out and stays cleaner. A north-facing roof sees less UV but stays damp, and green algae and moss take hold. Trees overhead drop leaf litter and sap that sit on the sheets and hold moisture against the seals. Our article on cleaning a conservatory roof safely explains how to slow that down.
Signs a polycarbonate roof is wearing out
Look for these from the ground and from inside.
- Yellowing or a milky haze. This is the outer layer breaking down in the sun, and it cuts the light in the room.
- Green or black growth inside the sheet. Water and algae get into the hollow channels when the end seals fail. You cannot clean this out from outside.
- Cracks and brittleness. A sheet that cracks along a fixing line, or snaps when pressed, has lost its flexibility.
- Drips and damp patches. Failed rubber gaskets or sealant at the bars and at the house wall let water through.
- Rattling or lifting sheets. Worn fixings and distorted bars let the sheet move.
How to get more years out of the roof you have
Routine care makes a real difference. Rinse the sheets with clean water and a soft brush a few times a year, and use a mild, non-abrasive cleaner for stubborn marks. Avoid pressure washers, which can force water past the end seals and lift the cap strips, and never use solvents or scouring pads on the plastic. Clear leaves and moss from the gutter and the bars, since standing water and debris are what rot the gaskets. Check the end caps and the sealant at the house wall once a year, and renew any that have cracked. A small repair done early is cheap, and it keeps water out of the sheets.
Also look at the room itself. Condensation that runs down the inside face of a sheet, or a smell of damp at the ridge, tells you the seals are working loose. Photograph anything you notice, with the date, because it helps when a repair is needed.
Repair or replace?
A roof with a few leaking bars or a loose cap strip is a repair job. Gaskets and end seals can be renewed, and individual sheets can sometimes be swapped. The point to check is the frame. If the glazing bars are sound, the roof can be re-sheeted with new polycarbonate or with glass. If the bars are corroded, bent or sagging, any new sheet will fail early, because the support is wrong.
When the sheets are old, yellowed and full of algae, and the frame has seen better days, replacement is usually better value than patching. Our guide on whether a conservatory roof can be repaired rather than replaced sets out what is worth saving.
What to replace it with
You have three main choices. A new polycarbonate roof is the cheapest and quickest, and it can last again if the sheet is good and the frame is sound. Glass costs more, improves light and the look from inside, and gives a better feel. Both stay hot in summer and cold in winter compared with the rest of the house. A solid tiled roof fixes the temperature and noise problem, at a higher cost and with a Building Regulations application. Our guide to glass, polycarbonate or solid conservatory roofs compares them side by side.
How we judge the time left
At the free survey we photograph the sheets, the seals and the bars, and look from inside as well as outside. A roof showing mild clouding but no leaks and a sound frame can run for several more years, and we will say so. We give you the photos, a fixed written quote for each realistic option, and a straight view of which one we would choose in your place. Our main page on conservatory roof replacement in Basingstoke has more.
Every roof is different. A free survey with photos settles it for yours.
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