Most windows whose handle is stiff, whose sash rubs on the frame or that let in draughts when closed can be fixed with a simple adjustment. We explain how to identify the cause from the symptoms and when parts need replacing.
“The window won’t close”, “the handle won’t turn all the way”, “there’s a whistling sound when it’s shut” or “the curtains move” are the complaints behind most service calls. The good news is that many of these problems are not faults but adjustments that have drifted over time. The bad news is that a simple adjustment issue left untreated can strain the hardware and turn into a real fault. In this article we explain how to tell the source of the problem from the symptoms.
Why do adjustments drift?
uPVC windows do not stay fixed for long after installation; the building settles, profiles expand and contract with temperature, and sashes are opened and closed every day. The difference between Muğla’s hot summers and cool, rainy winters can make profiles move a few millimetres over the year. Heavy sashes with insulated glass can sag slightly towards the hinge side over time. And if the glazing packers were not placed correctly, the sash goes out of square. All these factors change the delicate balance of a few millimetres between sash and frame.
Possible causes by symptom
| Symptom | Possible cause | Solution |
|---|---|---|
| Sash rubs on bottom frame, must be lifted to close | Sash sagging, hinge adjustment | Height and lateral adjustment; re-packing glass if needed |
| Handle won’t turn fully | Locking pin not engaging keep | Pin or keep adjustment |
| Handle very stiff | Dry hardware, excessive pressure setting | Lubrication, reducing pressure |
| Draught and whistling when closed | Low pressure, worn gasket | Pressure adjustment, gasket replacement |
| Sash goes into turn and tilt at the same time | Mis-operation lock disabled | Hardware check, urgent service |
| Air coming between frame and wall | Installation gap, foam or sealant failure | Renewing the installation detail |
| Water collecting in bottom corner | Blocked drainage, gasket or corner weld problem | Drainage cleaning, inspection |
The sash rubs or sags
If the sash hits the bottom frame while closing, or you need to lift it to lock it, it has most likely sagged. Tilt and turn hardware has a height adjustment on the bottom hinge and a lateral adjustment on the top stay. Drawing the sash towards the hinge side with the top stay raises the opposite corner. Slight sagging is corrected with these adjustments.
If the sagging is significant and adjustment is not enough, the problem may lie with the glazing packers. The insulated glass unit is carried in the sash by plastic packers placed at specific points, and these packers keep the sash square. If they have shifted or are missing, the glazing beads must be removed and the glass re-packed. This is specialist work; incorrect packing can crack the glass unit.
Draughty when closed
If the curtain moves, a candle flame flickers or you hear whistling on windy days while the sash is closed, there are three possibilities. The first is that the locking pins are still in the summer position; eccentric pins can be turned to increase pressure. The second is that the gasket is worn, hardened or separated at a corner; in that case it must be replaced. The third is that the airflow is coming not from the sash, but from between the frame and the wall.
You can do a simple test to find the source: trap a sheet of A4 paper between sash and frame, close the window and pull the paper. If it slides out easily, the pressure at that point is insufficient. Trying at several points around the sash lets you identify the weak area. If the paper is tight everywhere but air still comes in, check the installation gap and the inner and outer sealant around the frame.
The handle won’t turn or jams
If the handle jams halfway, one of the locking pins is usually not seating fully in its keep. Open the sash and check the pins and keeps; a displaced keep with loose screws may be the culprit. Lubricating the hardware also reduces stiffness. If the handle is broken or spins freely, the handle or its internal gear mechanism needs replacing. Forcing the handle can break internal parts of the hardware, so do not apply force to a stiff handle.
A dangerous sign: the sash in two positions at once
If, on a tilt and turn window, the sash both swings open sideways and tilts from the top while the handle is in the wrong position, the mis-operation lock has failed. In this situation the sash may be hanging only from the bottom hinge and there is a risk of it falling. Try to close the window without forcing it, supporting the sash, and avoid using it if possible. This symptom always requires a service visit.
Fault or adjustment? A quick checklist
- Parts intact, only alignment off: adjustment.
- Gasket torn, hard or crushed: part replacement.
- Handle, hinge or stay broken or cracked: part replacement.
- Air and water around the frame: installation repair.
- Cracked profile, opened corner weld: sash or frame renewal.
In holiday homes and guesthouses, doing these checks before the season starts prevents guest complaints and waiting for service at the busiest time. Since service requests rise sharply in our area in May and June, planning maintenance and adjustment work in early spring is an advantage.
Conclusion
Most windows that will not close or let in draughts can be fixed quickly with the right diagnosis. You can make simple pressure adjustments and lubricate the hardware yourself; sagging, broken hardware, gasket replacement and installation-related air leaks, however, need an expert check. Our team inspects on site to determine whether the problem is an adjustment or a fault, and offers a free site survey and measurement if renewal is needed.
