Conservatory roofs leak in a small number of predictable places, and the good news is that most of them are repairable for a fraction of a replacement. The bad news is that polycarbonate has a service life, and once the sheets have gone brittle and cloudy the sensible repairs run out and every fix becomes temporary.
Where a leaking conservatory roof actually lets water in
The commonest is the flashing where the roof meets the house wall, which was often a self adhesive strip that has lifted. Next is the end cap or the sealing tape on the open ends of polycarbonate sheets, which lets water and insects into the flutes and shows as a stained cloudy panel. Then the glazing bar gaskets, which perish and let water past the cap. Then the box gutter, on conservatories that have one. Almost none of these need the roof taken off.
How to fix a leaking conservatory roof: the repairs worth doing
Replacing the wall flashing with a properly dressed and pointed one is the highest value repair on a conservatory and it is roofing work rather than glazing. Re-taping the sheet ends and renewing the end caps cures the stained panels. Replacing perished gaskets on the glazing bars is fiddly and cheap. Clearing and resealing a box gutter stops the leak that appears to come from nowhere in heavy rain. A competent installer will quote for these individually rather than only for a new roof.
What sealant can and cannot do
A bead of sealant along a lifted flashing or a glazing bar cap will often stop a drip for a season, and that is all it is. Sealant over a dirty or wet joint does not bond, and it hides the gap. A conservatory roof is sealed properly by renewing the part that failed: a dressed flashing at the wall, new tape and end caps on the sheets, and fresh gaskets on the bars.
When patching stops making sense
Polycarbonate goes brittle with ultraviolet exposure, and past a certain age the sheets crack when they are handled, which makes any repair that involves lifting one a gamble. At that point the arithmetic changes: a replacement polycarbonate conservatory roof in modern sheet is a day's work and restores the whole roof, while another season of repairs restores one panel. If two or more sheets have already cracked, price the replacement.
Never stand on a conservatory roof
A conservatory roof is a fragile surface. Polycarbonate sheets and glazing bars are not designed to carry a person, glass roof panels are not a walking surface unless specifically specified as one, and the aluminium bars between them will not take a foot. Falls through fragile roofs are a recognised category of serious and fatal injury and the HSE treats rooflights and similar surfaces as a named hazard for exactly this reason. Work on a conservatory roof is done from a tower, a scaffold or a crawling board arrangement that spans onto the structure, and any contractor who steps straight onto the roof is telling you something about how they work.
Questions people ask about conservatory roof repairs
Why is my conservatory roof leaking at the wall?
Almost always the flashing. Many conservatories were finished with a self adhesive strip against the brickwork rather than a lead or metal flashing dressed into a chase, and those strips lift within a few years.
Can a single polycarbonate panel be replaced?
Yes, and it is a common repair after impact damage. On an old roof the risk is that removing the cap and lifting the neighbouring sheets cracks them, which is why age changes the calculation.
Does a conservatory roof repair need building regulations approval?
Repairs and like for like sheet replacement normally do not. Changing the roof to a solid one is a different matter and commonly does.
Can you stand on a conservatory roof to clean it?
No. It is a fragile surface and neither the panels nor the glazing bars are designed to carry a person. Cleaning is done from the ground with a pole system, or from a tower or scaffold.
What does replacing the whole conservatory roof cost instead?
Snug Conservatory Solutions gives £2,000 to £7,000 on average for replacing a conservatory roof, depending on the materials, the size of the roof and the complexity of installation. That is the figure to set against another round of repairs on brittle sheets.
Can I fix a leak in a conservatory roof myself?
The checks can be done from the ground and from inside: look for a lifted flashing at the wall, stained or cloudy sheet ends and a blocked gutter. The repair itself means working on or over a fragile roof, which is a job for someone with a tower or scaffold and the right access equipment, never from a ladder resting on the roof.