Why Won't My uPVC Window Stay Open?
For an outward-opening uPVC casement window that slowly falls or swings shut instead of staying at the angle where you leave it.
What this usually means
A uPVC casement window that will not stay open usually has worn or loose friction stays—the metal hinge arms designed to hold the sash at intermediate positions. Some stays have an adjustable friction screw, while badly worn, bent or corroded stays need replacement. The sash can be surprisingly heavy, so a window that drops suddenly should be supported and repaired rather than wedged open permanently.
What may be causing this
The friction setting has become too loose
Clues: The stay looks intact and the window closes smoothly but no longer holds position.
What to do: On adjustable stays, a small manufacturer-appropriate friction adjustment may restore holding force.
The friction stays are worn out
Clues: The sash creeps shut despite adjustment or the stays are old and polished at the friction points.
What to do: Replace the stays as a matched pair suited to the sash size, weight and opening type.
A stay is bent, corroded or damaged
Clues: One side moves differently, catches, twists or looks visibly distorted.
What to do: Replace damaged hardware rather than trying to bend it back.
The sash has dropped or become misaligned
Clues: The window also catches the frame or shows uneven gaps when closing.
What to do: Realign the sash and replace worn hinges if necessary.
How to check what is happening
The friction stays are no longer providing enough holding force.
Replacement is more appropriate than simple adjustment.
The hinge problem may also have allowed the sash to drop out of alignment.
A minor adjustment may be worth trying before replacement.
Can you fix this yourself?
A small friction adjustment may be manageable on an easily accessible ground-floor window if you can safely support the sash. Replacing stays requires supporting and partly releasing the window sash, so upper-storey or heavy windows are better handled by a window fitter.
- Screwdriver appropriate to the hinge
- Suitable lubricant if recommended
- Window support or helper
- Replacement matched friction stays if needed
What you can safely try
- 1
Support the window sash
Do not begin hinge work while relying on the worn stay to hold the window open.
- 2
Inspect both friction stays
Look for corrosion, bent arms, loose fixings or obvious wear on either side.
- 3
Adjust friction only if the stay is designed for it
Use small changes and retest. Do not overtighten until the window becomes difficult to operate.
- 4
Check how the sash closes
A hinge that has worn enough to lose friction may also have let the sash drop and catch the frame.
- 5
Replace worn stays as a matched pair
Use the correct size, stack height, opening type and load rating so the sash remains safe and aligned.
Call a window fitter if…
- The window is on an upper floor with unsafe access.
- The sash is heavy or difficult to support.
- A hinge is cracked, detached or badly corroded.
- The window is an emergency-egress window and the correct stay type is uncertain.
- The frame fixing points are damaged.
Get the right window fitter.
We already know this problem maps primarily to a window fitter. Choose the closest type of work, add your postcode and continue in the form.
Sources used for this guide
We prefer primary UK guidance, regulators and manufacturers for technical and safety-sensitive claims.
- How to Adjust UPVC WindowsScrewfix
- uPVC Window Hinge Repair & ReplacementMax the Locksmith
Last reviewed: 1 September 2026. Home Manual updates review dates only when the substance of a guide is checked or changed.