Replacing a polycarbonate conservatory roof
Polycarbonate roofs fail in a predictable order: discoloured, then noisy, then leaking at the glazing bars. The question is whether to replace it with the same thing or use the money differently.
Why polycarbonate roofs fail
- UV degradation. The protective layer breaks down and the sheets yellow, cloud and go brittle, usually from year 10.
- Algae in the flutes. Green staining inside the multi-wall channels that no amount of cleaning reaches.
- Gasket and glazing bar failure. The rubber seals shrink and harden, which is where nearly every polycarbonate leak starts.
- Storm damage. Panels lift at the ridge in high winds because the sheets are light and the retaining caps are old.
None of that is repairable in any lasting way once it is widespread. Individual panel or gasket replacement at £150 to £400 is worth doing if the rest is sound.
What replacement costs
| Option | Typical cost | What changes |
|---|---|---|
| Individual panels and gaskets | £150 – £400 | Stops one leak |
| Full like-for-like polycarbonate, 25mm | £1,500 – £2,600 | Clean and watertight again |
| Full like-for-like, 35mm multi-wall | £2,000 – £3,500 | Slightly warmer and quieter |
| Upgrade to glass | £4,000 – £7,500 | Far better light quality, quieter, warmer |
| Upgrade to solid insulated panels | £5,000 – £12,000 | Usable through winter |
| Upgrade to lightweight tiled | £7,500 – £16,000 | Reads as a room, not a conservatory |
When like for like is the right answer
Three situations, honestly:
- You are selling within a year or two and want the conservatory presentable rather than transformed.
- The room is genuinely a garden room: plants, storage, summer use only.
- The frame will not carry anything heavier and strengthening it does not stack up.
In every other case, the £2,500 spent on new polycarbonate is £2,500 that does nothing about the reason you avoid the room from October to April.
What the job involves
A like-for-like replacement is a one-day job on a standard conservatory. The installer strips the old sheets and caps, checks and usually renews the glazing bar gaskets, cuts new sheets to size with the flutes running down the fall, fits end caps and breather tape to stop dirt getting inside the channels, then re-seals at the wall plate and ridge. Ask specifically whether new gaskets and end tapes are included, because leaving the old ones is how a new roof leaks in year two.
Do you need permission?
For like-for-like polycarbonate, no: it is a repair. Switching to a solid roof is different and needs building control sign-off, covered in conservatory roof building regulations. If you are weighing the options, glass, tiled or polycarbonate compares all four on cost, warmth and light.
Only the temperature bothers you? Insulating a conservatory roof covers the cheaper halfway options.
Compare polycarbonate against the alternatives
Three free quotes from vetted local installers, priced for your conservatory, so the comparison is real rather than theoretical.