The short answer
Repair a conservatory roof when the problem is one defined fault, such as a failed seal, a cracked sheet or a split flashing, and the frame and glazing bars are sound. Replace it when leaks keep returning in new places, the glazing is brittle or stained, or the room is too hot or cold to use. One leak is a repair. A pattern of leaks is a verdict on the roof.
The question that decides it
Most conservatory roof problems begin as a drip, and a drip tempts people into a quick sealant job. Sometimes that is exactly right. Sometimes it buys a few months before the next drip appears two panels along. What separates the two cases is how far the fault spreads.
A local fault has one cause you can point to: a cracked pane, a section of perished rubber gasket, a lifted lead flashing along the house wall, a blocked gutter spilling behind the frame. A general fault has no single cause because the whole roof is tired. The seals have hardened everywhere, the sheets have gone brittle, the glazing bars are corroding or the frame has moved. Patching a general fault means chasing leaks around the roof one at a time.
Before you decide, find out which sort you have. A roofer on the roof, looking at the sheets, the bars, the ridge and the wall junction, can usually tell in one visit.
When repair is the sensible choice
Repair holds up well in these situations.
- A single cracked sheet or pane. Replacing one unit is a small job if the frame is solid and the unit can be matched.
- Failed sealant or gaskets in one area. If the rest of the seals are supple and the leak is traced to a short run, resealing is reasonable.
- A lifted or split flashing. The lead dressed into the house wall is a common source of water. A flashing is the metal weathering, usually lead, that seals the gap between roof and brickwork. Reworking it is a proper repair, not a plaster.
- Blocked or sagging gutters. If water is being thrown back under the roof edge, cure the drainage before you blame the roof.
- A young roof with a defect. A roof of recent date with one fault suggests a fitting slip, which is correctable.
Typical UK figures from MyBuilder (2026) put an average roof repair at £150 to £1,500, with a small leak at £100 to £300. Treat these as a sense of scale: the quote you actually pay is fixed after the survey. Our conservatory roof repair guide goes through the individual jobs.
When replacement is the better value
Replacement makes sense when repairs have stopped holding. Some signs are plain on the inside of the room.
- Leaks that move. You fix one corner and a different joint starts to drip. That is the seals failing as a set.
- Brittle, yellowed or cloudy sheets. Polycarbonate weathers in sunlight, goes opaque and cracks when touched. Sources such as HomeBuilding put a polycarbonate roof at roughly ten years, and The Eco Experts at ten to fifteen, so an older roof is on borrowed time.
- Corroded or distorted bars. If the glazing bars are rotting or bent, new sheets will not seal against them.
- An unusable room. If the conservatory is freezing in January and overheated in July, no amount of resealing will change that. A better roof will.
For perspective, MyBuilder's 2026 guide gives £2,000 to £10,000 or more for a replacement, averaging about £4,500, with a tiled roof averaging about £4,000. Those are national figures for planning purposes, and we price your roof on its own measurements. If you want to know what lasts, HomeBuilding reports glass at over 30 years and tiled roofs at over 50.
Checking the frame and the base
The decision depends on the frame at least as much as on the sheets. A conservatory roof performs only as well as its supporting structure, and a replacement is the moment to look at that structure properly.
Check the ridge and the eaves beam for movement or rot. Look at the frame joints for gaps, and at the glazing bars for flaking, corrosion or splits where they meet. In older timber frames, damp at the foot of the rafters and at the wall plate is a common finding. If the frame is straight and dry, a new roof can usually go straight on it. If it has moved, a new roof will not cure that, and putting heavy materials onto a weak frame is worse than leaving it alone.
That is also why anyone considering a solid or tiled roof needs a structural look first. The jump in weight from polycarbonate is large, and the base and low walls may need strengthening. Some owners keep a sound frame and change only the roof, which is often the cheaper route if the frame passes the check.
Paperwork that follows a replacement
A like-for-like swap of sheets or glass is a lighter job administratively than a change to a solid roof. Going solid is classed as material alteration, so a Building Regulations application is required. Planning can be a separate question, especially in a conservation area or on a listed house, which our answer on conservatory roof planning permission explains.
It is worth settling this before choosing between repair and replacement. If a repair would only delay a roof you plan to replace anyway, the paperwork might as well be started early. The details of the solid option are in the guide to a solid conservatory roof.
A fair way to compare the two routes
Put the repair cost next to what replacement would cost spread over the years it buys. A repair that lasts several years beats a new roof on value. One that survives a single wet winter does not. Ask the roofer what they expect the repair to achieve and for how long, and ask which other parts are close to worn out. If the answer lists several items, replacement is probably the honest recommendation.
We favour repair wherever repair will hold. We survey the roof for free, photograph what we find on your actual conservatory, and put a price on the option that fits its condition, along with a note of which parts we expect to need attention next. How long polycarbonate can last before it gets that far is the subject of our page on polycarbonate roof lifespan, and the wider picture is on the conservatory roof replacement page.
