Conservatory Roof Panels: Repair, Replace or Change the Roof?
Updated: 9 hours ago
Conservatory roof panels are the individual glazed or polycarbonate sheets that sit between the roof bars of a conservatory, and they are the part of the roof that fails first. A cracked, discoloured, leaking or misted panel is the usual reason people start looking at their conservatory roof, and the choice is between replacing the panel, replacing all the panels with better ones, or replacing the roof. Which one is right depends on what the panel is made of, how old the roof is and what you want the room to do.
What are conservatory roof panels made of?
Two materials cover almost every conservatory roof built in the last thirty years.
Polycarbonate panels are multi-wall translucent polymer sheets, usually 16, 25 or 35 millimetres thick, with hollow flutes running along them. They are light, cheap and easy to fit, which is why so many roofs have them. They are also the reason so many conservatories are too hot in summer, too cold in winter and noisy in rain, and they age visibly.
Glass panels are sealed double glazed units, sometimes with a solar control coating on the outer pane and a low-emissivity coating on the inner. They are heavier, so the roof bars and the frame need to be designed for them, and they cost more. They keep the room warmer, cooler, quieter and clearer, and they last far longer.
Typical figures, which vary by manufacturer and should be checked on the product data:
16mm polycarbonate: a U-value of roughly 1.8 to 2.0 W/m²K, about 2.5 to 3kg per square metre.
25mm polycarbonate: roughly 1.5 to 1.7 W/m²K, about 3 to 3.5kg per square metre.
35mm polycarbonate: roughly 1.3 to 1.5 W/m²K, about 4kg per square metre.
Double glazed roof unit with low-emissivity coating: roughly 1.0 to 1.3 W/m²K as rated, somewhat higher once laid at a shallow roof pitch, and 20 to 30kg per square metre depending on the pane thicknesses.
The lower the U-value, the less heat escapes. The weight column is why a roof built for polycarbonate cannot simply be reglazed.
Our conservatory roof types post compares glass and polycarbonate against solid and hybrid roofs; this one is about the panels themselves.
How do conservatory roof panels fail?
Polycarbonate fails in four ways. It yellows or goes cloudy as ultraviolet light breaks down the surface, usually within ten to fifteen years. The flutes fill with algae, dust and condensation because the end tapes have failed, which shows as green or grey streaks. It cracks, from impact or from the sheet expanding and contracting against fixings that were too tight. And it lifts or slips in high wind if the end caps and bar cappings have degraded, which is where leaks start.
Glass panels fail differently. The most common fault is a misted unit, where the seal around the edge has failed and moisture has got between the panes. The glass itself rarely fails; a cracked pane is usually impact. Leaks on a glass roof are almost always the bar cappings, gaskets or the ridge, not the panel, and blocked gutters and moss speed both failures up, which is why our guide on how to clean a conservatory roof is worth following twice a year.
Can you replace a single conservatory roof panel?
Yes, on most roofs, and it is the right repair for a single cracked panel on a roof that is otherwise sound. The bar capping is removed, the panel is lifted out, a new panel of the same size and thickness is fitted with new gaskets and end tape, and the capping goes back. A single polycarbonate panel is a straightforward job; a single glass unit needs the exact size and specification of the original and two people to lift it, because toughened glass cannot be cut down to fit.
The reasons not to replace a single panel are the ones that make the whole roof the problem. If the other panels are yellowed, replacing one leaves you with one clear panel in a cloudy roof. If the bar cappings and gaskets are perished, the leak will move to the next bar. If the roof is polycarbonate and the room is uncomfortable, a new polycarbonate panel does not change that.
Should you replace polycarbonate panels with glass?
Sometimes, and it is the upgrade that changes a conservatory most for the money, but it depends on the structure. Glass units weigh several times what polycarbonate does, and a roof designed for polycarbonate may not have the bar sections, ridge, eaves beam or frame to carry glass. A structural check comes first.
Where the frame can take it, replacing all the panels with solar control double glazed units keeps the existing roof bars and gives most of the benefit of a new glass roof: cooler in summer, warmer in winter, quieter in rain, with a clear view of the sky. The bar cappings and gaskets are renewed at the same time, which deals with the leaks. Where the frame cannot take it, the answer is a new roof, and often a new conservatory.
When is the whole roof the answer?
Replace the roof rather than the panels when the bars, ridge or eaves beam are failing, when the frame below is moving, or when the roof is polycarbonate and the frame cannot take glass. A new glass roof, a solid or hybrid roof, or a flat insulated roof with a roof lantern each turn the conservatory into a different room. Our guide to conservatory roof replacement cost explains what drives the cost of each route, and our luxury conservatories are built with glass or lantern roofs on frames engineered for them.
Conservatory roof panels questions, answered
How long do conservatory roof panels last?
Polycarbonate panels typically look tired within ten to fifteen years and are usually replaced by twenty. Sealed glass units last around twenty years before seals begin to fail, and the glass itself far longer.
Why is my conservatory roof panel misted?
On a glass roof, a misted panel is a failed sealed unit: the edge seal has let moisture between the panes. The unit is replaced; the panel around it is usually fine. On polycarbonate, cloudiness is the sheet ageing and cannot be reversed.
Is it worth replacing conservatory roof panels or the whole roof?
Replace panels when the structure is sound and the fault is a panel. Replace the roof when the bars or frame are failing, or when you want a room for all seasons.
Talk to our design team
If your conservatory roof is the reason the room is not used, we are happy to look at it with you and say plainly whether the panels, the roof or the conservatory is the answer.
