Slipped Conservatory Roof Panel

What's happening?

A conservatory roof panel is not fixed rigidly. It sits on gaskets in an aluminium glazing bar, held at the bottom by a stop or clamp at the eaves, and it is meant to be able to move a little with temperature. When the panel slips, that restraint has failed: the eaves stop has come loose or worn, or the gaskets it slides on have shrunk and lost their grip. Once it has moved, the gap opens at the ridge and rain runs straight in. Polycarbonate slips more readily than glass because it is lighter and expands far more, and the slip usually accelerates: each season's expansion moves it a little further down the bar and it never comes back up on its own.

What usually causes it?

• Eaves stop, clamp or panel retainer loose, corroded or missing
• Glazing bar gaskets shrunk and hardened, so the panel is no longer gripped in the bar
• Thermal expansion and contraction of polycarbonate ratcheting the sheet down the bar over years
• Roof pitch too shallow for the system, so the panel is always working downhill
• Structural movement of the conservatory frame or the ring beam, opening the bar spacing
• Panels walked on or loaded during cleaning or gutter work
• An earlier repair that sealed over the ridge gap instead of re-securing the panel at the eaves

Is it dangerous?

Treat it as such. This is overhead glazing above a room people sit in, and a panel that has already moved is a panel whose restraint has failed: glass roof panels are heavy, and polycarbonate sheets are large and stiff enough to injure. Keep the conservatory out of use where a glass panel has slipped noticeably. The secondary damage is water: run-in at the ridge gets into the ring beam, the wall plate and the internal finishes, and it usually reaches those before anybody links it to the panel.

Can I fix it myself?

Almost nothing, and this is the clearest case in this category. Do not go onto a conservatory roof: the panels are not a walking surface and the frame is not designed for point loads, and this is where falls through roofs happen. Do not push a slipped panel back up from below, because that removes the little support it still has. Clearing the gutters and moving furniture out from under it are the useful things to do from the ground.

When should you call a glazier?

Call a glazier or conservatory specialist promptly, and treat a slipped glass panel as urgent. Say which material it is and how far it has moved, because a glass panel that has crept two centimetres is a different level of urgency from a polycarbonate sheet that has eased down. Also mention any water staining inside, since that decides whether the frame needs looking at as well as the panel.

What will the glazier actually do?

• Access the roof safely from staging or a tower rather than from the roof itself
• Ease the panel back up the bar into its correct position at the ridge
• Renew the eaves stops, clamps and panel retainers that let it move
• Replace shrunk or hardened glazing bar gaskets along the full length of the bar
• Reseal the ridge and eaves details and confirm water is being carried out to the gutter
• Check the remaining panels and the ring beam for the same slippage and for water damage

Questions people ask

Sources & References

1. HSE: Roof work
2. GOV.UK, Protection from falling, collision and impact: Approved Document K
3. Glass and Glazing Federation