The short answer
Yes. A single polycarbonate sheet or glass unit can be replaced without renewing the whole conservatory roof, provided the frame and glazing bars are sound. The old panel lifts out from between the bars and a new one of the same size and type goes in with fresh seals and caps. Colour and thickness need matching, and the reason it failed needs finding.
One cracked or misted panel is a tidy job. Getting the size, thickness and sealing right is what keeps it from leaking later.
How a single sheet comes out and goes in
A glazed conservatory roof is a row of panels lying between glazing bars, the rails running down the slope from ridge to gutter line. Each panel is held by a cap, a cover that clips over the bar and grips the panel edge, and sealed with tape or a rubber gasket.
What happens on the day?
The roofer opens the caps either side of the faulty panel, frees the seals and lifts the sheet out. The bars are then cleaned and checked for corrosion, loose fixings or a bent section. The new panel is measured to the opening, cut to size if it is polycarbonate, and laid in with new tape or gaskets, then the caps are refitted. The ends of a hollow polycarbonate sheet are sealed so dust, damp and insects cannot get into the cells.
Access matters as much as the sheet. A conservatory roof is fragile, so the work is done from a crawling board or a platform that spreads the load, not by stepping on the roof. That is part of how we plan the visit and decide whether a ladder is enough. If water has been getting in, we also look at the wall plate and the head of the frame beneath, since a panel that leaked for months can leave damp timber that needs attention before anything new goes on.
Polycarbonate or glass: how each is replaced
The two coverings behave very differently when one panel fails, and it is worth knowing which you have before anybody quotes.
Can a polycarbonate sheet be swapped alone?
Usually, yes. Polycarbonate is cut to the opening, so a replacement for a single bay is simple. The sheet should be the same thickness as the others, or it will sit proud of its neighbours or sag in the gap. Note the colour too: clear, opal and bronze tints exist, and a bright new sheet beside yellowed old ones will show.
What about a glass unit?
A glass unit is a sealed double glazed panel made to size, so a replacement is ordered to the measured opening and takes time to arrive. A unit that has misted inside has lost its seal, and it needs replacing, since drying out the cavity is not a lasting fix. Glass is heavy, so lifting it needs more than one person and the right equipment. Our answer on fitting glass in place of polycarbonate covers the weight question across a whole roof.
When one panel is not the answer
Replacing one panel is a good repair on a healthy roof. It is a poor one on a roof that is failing everywhere.
Why did this panel fail?
A single crack from a stone, a branch or a ladder is bad luck. A crack with a pattern, where several sheets show hairlines or yellowing, is age. Published guides give polycarbonate roofs a typical life of about 10 to 15 years, so a panel failing on an older roof often has neighbours about to follow. Our guide on repairing or replacing a conservatory roof sets out how to weigh it.
Movement is the other cause. A panel that cracks near a bar can be a sign of a frame that is moving, or of a sheet that was fixed too tightly and could not expand in the heat. Swapping the sheet without curing the cause means the next one splits in the same place.
Leaks, seals and the cost
Many leaks that look like a bad panel come from the seal or cap beside it. Before you order a new sheet, look for a lifted cap, a gap in the gasket or old sealant that has shrunk back from the bar. Replacing a seal costs far less than replacing a sheet. A new sheet or unit is also the moment to renew the cap and tape on both sides of it, which is easy while the bars are open and saves a second visit.
What does a panel replacement cost?
The price depends on the panel type, its size, the number of panels, how awkward the roof is to access, and whether a glass unit has to be made to order. Because those things vary roof to roof, we price after a survey and give one written total.
Send us a picture of the failed panel from inside, one of the outer edge if it is visible from the ground, and the approximate size of the room. We take pictures of the surrounding bars and caps at the survey and show you what we found. For the wider choice of coverings, see our conservatory roofs page.
More on swapping a roof panel
Will a new panel match the old ones?
Thickness and size can be matched exactly. Colour is harder, because old polycarbonate yellows and a fresh clear sheet looks brighter beside it. If the match matters, a sheet taken from a hidden corner can be moved to the front and the new one fitted where nobody looks, or the whole roof can be done at once.
Can I replace a conservatory roof panel myself?
A confident person can swap a polycarbonate sheet from a safe platform, but the roof is fragile and a fall through it is serious. Glass units are heavy and easy to damage. Sealing the sheet ends and caps properly decides whether the roof leaks, so many owners ask a roofer to do it.
The full picture: Conservatory roofs in Taunton ยท More short answers