The short answer
Mend a conservatory roof on a sound frame, when the fault is small: a single cracked sheet, a worn seal or a loose cap. Replace it when the sheets are failing across the roof, leaks keep returning or the roof has reached the age published guides give for its covering, about 10 to 15 years for polycarbonate. Patching a finished roof means paying twice.
The cheaper job is not always the better buy. Age, the number of faults and the state of the frame settle which way to go.
Faults that a repair really fixes
A repair suits damage confined to one spot, where the parts around it are healthy. Conservatory roofs have a short list of those faults, and most are cheap to put right.
Which problems can be mended?
A single cracked or holed sheet can be replaced on its own. A cap, the plastic cover that grips the sheet edge over each glazing bar, can be refitted or renewed. A perished rubber seal or glazing tape can be changed, and a short run of failed lead or sealant along the house wall can be redone. Blocked gutters and a loose ridge cap also fall under repairs.
These jobs stop leaks and drafts, and they leave you with a roof that is no worse than it was. What they cannot do is give a worn covering a second life. If the sheets beside the repair are yellowed and brittle, the next fault is only a matter of time. Our answer on replacing a single roof panel sets out when one sheet is enough.
Signs the whole roof is finished
Replacement makes sense when faults are spread out, not single. Cloudy or yellowed sheets across the whole roof, cracks in several places, damp at more than one bar and growth inside the cells all tell the same story. Small faults tend to arrive together as a covering ages, so a list of three or four problems across the roof is a stronger sign than any one of them.
How old is too old to repair?
Age is the quickest guide. For polycarbonate, HomeBuilding gives a typical lifespan of 10 years, and The Eco Experts about 10 to 15 years for glass or polycarbonate. Both are typical figures rather than promises, and a roof inside that window can still be perfectly sound. A roof well beyond it, with several faults showing, is the strongest case for replacing the lot.
Repeat leaks are another sign. If you have had the same bar resealed twice and it drips again, the trouble is usually the sheet, the bar or the frame beneath, and sealant on top will not cure it. Our answer on how long polycarbonate lasts sets out what shortens a roof.
What the frame tells you
Whatever goes on top depends on what holds it up. Before deciding, look at the frame and the base the roof sits on.
Can the frame take a new roof?
If the frame is rotten, bowed, corroded or visibly sagging, it will not carry anything well, and the money belongs in the frame first. If it is straight and sound, a new covering goes on it. That covering can be fresh polycarbonate, glass or a tiled solid roof, and each weighs differently. Glass and tiles are heavier than plastic sheets, so the frame must be checked for them. If the frame is in doubt, the survey report tells you, with pictures, before any covering is chosen.
Under Planning Portal guidance, Building Regulations apply when the roof of a conservatory is replaced, and they look at structure, energy use and ventilation. Patching one sheet is a different matter, so the choice between repair and replace is also a choice about sign-off. We check the frame, the wall junction and the sheets together at the survey, then say what a repair would and would not fix.
Weighing the cost of each route
A repair costs less today. A replacement costs more today and less over a decade if the roof was close to done. Here is a fair test: if you expect to be calling someone back within a year or two, replace.
What does replacing cost?
Replacement is where the national guides have figures. MyJobQuote puts conservatory roof replacement at £3,200 to £6,000 (Oct 2026), and The Eco Experts at £2,300 to £6,000. Size, shape, covering, frame work and access push it up or down within that range. A repair is priced by how many parts are involved and how awkward the roof edge is to reach. Remember too that a replacement resets the clock: a fresh covering starts its life with sound seals and caps, where a repaired old one carries its past with it.
If you cannot decide, we survey first, take pictures of every sheet, cap and seal, and the quote we write afterwards gives one total for the route that fits the roof in front of us. That can be a repair, a new covering or a solid roof. Our conservatory roofs page shows the three coverings side by side.
More on mending or replacing
Is a leaking conservatory roof always a replacement job?
No. Many leaks come from a perished seal, a lifted cap, blocked gutters or worn flashing at the house wall, and each is a small repair. A leak across several bars, or one that returns after resealing, points to failing sheets or a moving frame. We find the path of the water before pricing.
Does the roof's age alone tell me to replace?
Age is a prompt to look, not a verdict. A polycarbonate roof past 10 years is in the range the guides give, so inspect it closely. Replace when age combines with yellowed sheets, cracks, repeat leaks or a tired frame. A sound roof with one fault can still be mended.
The full picture: Conservatory roofs in Taunton · More short answers