The four faults
A dropped leaf
The most common call. Hinges wear or their fixings loosen in the profile, and the leaf stops hanging square. It shows as the leaf catching on the frame at the latch edge, a widening gap at the top corner, and a door that needs lifting to close.
Most modern door hinges adjust in two or three planes, so a dropped leaf can usually be lifted back square. Where the hinge itself has worn, it is replaced. What we do not do is ease the frame to accept a dropped leaf — that makes the fault permanent.
Worn rollers and tracks
On sliding and folding doors, the whole leaf weight runs on small rollers in a track at floor level, which is exactly where dust collects. The progression is predictable: slightly heavier, then a grinding feel, then the leaf jumping or dropping.
Replacing rollers at the second stage saves the track. Leaving it to the third means the track needs re-capping too. On folding systems the track also has to be re-levelled, because a folder that is not running level will never fold squarely.
Failed locking
Multi-point gearboxes are wear items with a finite number of cycles. When one fails, the handle turns and nothing engages — and because those locking points also pull the leaf onto its gasket, the door stops sealing at the same moment. It is a mechanism replacement, not a handle replacement.
Hardened seals
Gaskets lose elasticity under heat and UV. Once they stop springing back, the door leaks air, sound and driven rain even when shut, and it rattles in wind. The same principles apply as on window sealing.
Thresholds and water
A balcony or terrace door has an opening at floor level, so it gets a category of its own. Water appearing inside is nearly always one of:
- blocked threshold drainage, backing water up over the upstand
- the leaf not pulling down onto its threshold gasket, which is a locking adjustment
- a failed perimeter seal at the jambs, letting water track down inside the frame
All three are repairs. None of them means the door is finished.
When we say replace
When the frame has rotted or corroded through, when it has moved permanently out of square, or when the system’s hardware is obsolete and no replacement gearbox or carriage exists. That last one is more common than people expect on older imported systems, and we check it before quoting rather than after.
In those cases see door replacement.
Tell us the door type, roughly how old it is, and exactly what it does. That is usually enough for us to name the fault before arriving.