Usually it is not the mechanism but something small: sand in the guide, a frame out of true, a displaced catch or a slackened cord in a pleated screen. You can check all of it yourself in a few minutes, and half of these cases resolve without a visit.
01NOTE EXACTLY WHERE IT STOPS
Binding right at the end means debris at the far point of the channel. Stiff along the whole run means sand and rollers. Skewing on the diagonal means the frame or one roller sitting higher.
02ON A PLEATED SCREEN IT IS USUALLY THE CORD
The fabric is held by the tension of the cord inside the folds. Once the cord stretches, the accordion stops gathering evenly.
03ON A ROLL-UP IT IS THE WINDING AND THE SPRING
If it winds crooked and drifts sideways, the winding is uneven. Sometimes unrolling the fabric fully and letting the spring take it back smoothly is enough.
04ON A HINGED SCREEN IT IS HINGES AND THE CLOSER
- The hinges have dropped and the leaf has sagged
- The closer has lost its adjustment and no longer pulls the leaf shut
- The magnetic catch has shifted and the leaf lands past it
- Cleaning changed nothing: this is now a repair
If it is a sliding screen
Notice where it stops. If it runs freely and jams right at the end, the culprit is the end stop or debris at the far point of the channel, where everything swept along the rail collects.
If it is stiff along the whole length, that is sand in the guide and worn rollers.
If it skews diagonally, either the frame has loosened or one roller sits higher than the other.
If it is a pleated screen
A pleated screen holds its shape on the tension of a cord running through the folds. Over time the cord stretches and the concertina stops gathering evenly: part of the fold opens and part does not.
The second cause is debris in the bottom guide. On pleated it is flat and low, so everything from the floor finds its way in.
The third is a skewed vertical bar. If you pull the handle at a corner rather than the centre, the bar travels at an angle and never reaches the post.
If it is a roll-up screen
The fabric usually fails to reach the bottom catch because the spring has weakened or the sheet is winding unevenly on the tube.
If it winds crooked and drifts to one side, that is uneven winding. Sometimes unrolling it fully and letting the spring take it back without jerks will settle it.
If the catch will not engage, check the receiving part on the sill: it may have moved.
If it is a hinged door
The commonest cause is the hinges: they have sagged and the leaf has dropped.
The second is the closer, which has lost its adjustment and no longer pushes the leaf home. In Dubai this typically needs setting once after the first hot months.
The third is a magnetic catch or strike plate that has shifted, so the leaf arrives beside it rather than on it.
Half of these cases are solved without a fitter: it is usually not the mechanism but sand, a skew or a knocked catch.
What to do next
Vacuum the guide with a narrow nozzle, wipe it and let it dry. Check that the rollers spin freely.
If nothing changes after cleaning, the fault is mechanical and it is a repair. Photograph the part close up and send it over: the picture shows the profile type, so the technician arrives with the right hardware rather than making a second trip.
