Why Is There a Draughty Gap on the Hinge Side of My uPVC Window?
For a casement uPVC window that closes and locks but leaves a visible or feelable gap near the top or bottom of the hinge side, causing a local draught.
What this usually means
A hinge-side gap often points to worn or distorted friction-stay hinges, poor sash guidance or reduced gasket compression rather than the glazing itself. ERA describes friction stays as the hardware that guides the sash and provides gasket compression, and GGF guidance says damaged hinges and seals are repairable window faults. If the sash is no longer pulling evenly into the frame, replacing correctly sized hinges is usually more effective than packing the gap with extra sealant.
What may be causing this
The friction-stay hinge is worn
Clues: The sash no longer pulls tightly into the frame at the hinge end.
What to do: Replace the stays as a matched, correctly specified pair where required.
The sash has dropped or lost guidance
Clues: The gap is uneven and the sash may also catch the frame.
What to do: Have alignment and hinge condition checked together.
The gasket has moved or deteriorated
Clues: The hinge geometry looks normal but the rubber seal is missing, flattened or displaced.
What to do: Refit or replace the correct weather seal.
Previous hinge replacement used the wrong stack height or size
Clues: The fault began after hardware replacement.
What to do: Use hinges matched to sash weight, size and profile.
How to check what is happening
Hinge wear or sash alignment is likely.
The sash hardware is probably not pulling the window in correctly.
Friction-stay wear is a strong suspect.
Can you fix this yourself?
Cleaning and reseating a loose gasket is reasonable if accessible, but friction-stay replacement must match window size, weight, stack height and opening type. A window fitter is safer for upper-floor or heavy sashes.
- Torch
- Paper strip for a simple compression comparison
- Phone camera
What you can safely try
- 1
Compare the gap along the hinge side
Look for one corner standing proud rather than assuming the entire seal has failed.
- 2
Inspect the rubber seal
Check whether it is present, seated and undamaged.
- 3
Watch how the sash moves
Sagging or sideways movement points toward worn stays or alignment.
- 4
Book correctly specified hinge repair
A fitter can match the stays and restore normal sash compression.
Call a window fitter if…
- The window is on an upper floor and the sash feels loose or unstable.
- A hinge is visibly detached or badly corroded.
- The glass or frame is under stress.
- Repair would require leaning outside.
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.
- Window Hinges & Friction StaysERA
- When to repair or replace your windowsGlass and Glazing Federation
Last reviewed: 2 September 2026. Home Manual updates review dates only when the substance of a guide is checked or changed.