This page is here to offer you free, practical advice if you're experiencing problems with your conservatory. Our aim is to help you understand how things should work, and to guide you in identifying common faults or areas of concern.
If you have a specific question or are dealing with a persistent problem, feel free to get in touch, as we’re always happy to help where we can.
Why Do Conservatory Roofs Leak? A Guide from the Experts
Leaks are one of the most common issues affecting conservatory roofs, and they can often be frustrating to trace. In many cases, the water ingress shows up far from the actual source of the problem, making repairs especially challenging without the right experience.
First, A Word on Conservatory Manufacturers
In our experience, having worked on hundreds of conservatories over the years , there’s really no such thing as a bad conservatory manufacturer. Most are mini-masterpieces of engineering. Some are more sophisticated than others, but that’s simply the result of progress and innovation over time.
So if we set aside poor installation or workmanship (more on that later), what are the main causes of conservatory roof leaks?
1. Old Age
Modern conservatories began appearing around the 1970s. That means many are now 30, 40, even 50 years old — particularly those installed during the boom of the '80s and '90s.
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uPVC Conservatories:
These structures usually remain sound, but the polycarbonate roof panels can become brittle or UV-damaged over time. Fortunately, replacing these panels is a straightforward solution. -
Faulty Wall Flashings:
Perhaps the most common cause of leaks in older conservatories. We often find the original foil-faced flashing has degraded into dust. While modern flexible adhesive flashings are far superior, earlier versions weren’t intended for long-term use.Removing old bitumen-based flashing can be tricky, especially from polycarbonate or uPVC, where it can leave residue and be difficult to bond over. Some manufacturers also advise against using bitumen-based products, as they may damage plastic components.
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Our solution: We often use modern butyl-based adhesive flashings, sometimes hidden behind traditional lead-style flashings to provide extra protection from the elements. We've also had excellent results with synthetic lead alternatives, which are ideal for low-pitch roofs and conservatories where conventional lead isn’t suitable.
2. Issues Specific to Older Timber Conservatories
Timber conservatories are often beautifully constructed but can suffer from a different set of age-related issues:
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Snap-Down PVC Bars:
These were a great idea — until they started going brittle. -
Aluminium Cappings with Exposed Screws:
These plastic-capped screws become exposed over time, leading to rusted fixings, water ingress, timber damage, and loose panels. -
Our approach:
We replace old bars with modern cappings that fully shield the fixing screws, improving durability and weather resistance. -
Fixing Buttons:
Those little mushroom-shaped buttons used to hold down the lower edges of panels often have foam seals that harden over time. If they're not renewed, leaks can develop.
3. Common Issues with Newer Conservatories
We’ve all heard stories about unfinished or poorly built conservatories. The good news is that these are relatively rare. Most professional installers do an excellent job.
Still, even a high-quality conservatory can have issues if something goes wrong during installation:
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DIY Builds & Builder Erected Conservatories:
Many conservatories are factory-made with incredible precision using CAD/CAM systems. The kits are accurate — but minor errors during base construction can throw off the whole structure.-
Result:
Misaligned or poorly seated roof panels, especially in Georgian or Edwardian styles, where triangular corner panels are vulnerable. -
What to look for:
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Misaligned panel edges along the eaves
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Skewed panels sitting improperly on glazing bars
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Beads of silicone used where none should be needed — a clear sign something wasn’t quite right.
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Missing Breather or Foil Tapes:
This can lead to panels filling with water, insects, moss, or dust in the air cavities. -
Condensation Inside Polycarbonate Panels:
This is actually normal and increases with age. However, manufacturers specify that: -
Sheet closers should be sealed with silicone, but
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Not over the breather tape — doing so can cause the adhesive to fail.
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Proper technique:
The silicone should be applied just inside the lip of the sheet closure or along the outer edge. The ends of the closure should also be sealed (provided there are drain holes at the bottom edge).
Conclusion: Most leaks are fixable with the right expertise
Conservatory leaks are common, but in the vast majority of cases, they are completely repairable. Whether it’s age-related wear, outdated materials, or installation faults, we have the experience to diagnose the issue properly and offer a practical, cost-effective solution.
From historic timber builds to newer uPVC structures, we’ve seen it all, and we’re always happy to provide straightforward advice to help you get the most from your conservatory.
A typical timber supported conservatory roof. The screws have worked loose, and the seals have perished . Just old age.
This panel on a two year old conservatory is cut at least 50mm short. It doesn't even overlap the timber eaves beam, never mind reach the gutter. Water was pouring inside. The panel didn't shrink in the rain, it was installed that way and whoever did it was happy to walk away knowing it was wrong, because all the other panels were correct. At the time of building, a new sheet would have been no great expense, but they still left it like this.
A brand new roof fitted by a supposedly experienced installer. The roof leaked from day one. After giving the company every opportunity to rectify the problem, we took off the cresting and spider cover to find this mess! Bear in mind this is a brand new roof and the client was charged over £6000. Probably spent that on sealer.
How not to fit a sheet closure. It should extend under the glazing bar and be sealed. Note the exposed breather tape. There is also a line of sealer along the edge of the glazing bar suggesting that the panel is only just resting on the rafter seal. All 20 panels on this newly re-roofed conservatory were like this. What's the excuse?
After recent giant hailstones in Leicestershire this is just one example of the damage they can cause to a conservatory roof.