Why Won’t My UPVC Windows Close?

UPVC window not closing

If your UPVC window is suddenly struggling to close, then it could be because of a variety of problems. Your locking mechanism, window hinges, rubber seal, window handle, or frame itself may have failed, moved, or become stuck. Figuring out which is the issue is the key to fixing your UPVC windows and ensuring your windows close so that you’re safe in your home again.

As window experts at Ultra-Seal, we see issues with UPVC windows all the time, which means we know how to fix the problem fast. You might need professional help to fix the windows, but our blog below might help you see that the issue is fixable on your own if you’re a competent DIYer.

Let us talk you through the possible problems with your window below, and help you find a useful solution.

Problems With Your Window’s Locking Mechanism

One of the most common reasons for a window not closing properly is a problem with the lock. Typically this is due to to the drive gear and keeps not lining into position correctly. It could also be a problem with espagnolette (or espag).

Note: Today we’re talking about issues where your window won’t close, but these could also be the problem if your window is stuck in the locked position and is unable to open.

How To Fix Your Window Lock

If the drive gear and keeps aren’t lining up, an allen key will fix it. Look for the roller cams on the edge of the window with an obvious slot for an allen key and then simply tighten it and test the lock. This is usually enough to fix it.

If the espag is the issue then you’ll have to replace it, rather than fix it. Remove the securing screws and take it away from the window and simply replace it with a new part in reverse. Tighten the screws to secure it in position and test the lock to see if it allows you to open and close the window effectively.

Problems With Your Window Hinges

A window hinge can wear down over time with continued use, and this is especially obvious with the bottom hinge, where you’ll notice it moving away from the sash and casement, leaving a gap between the hinges and the frame on the hinge side.

It’s also possible that the hinges aren’t entirely worn, but simply need adjusting because of particularly harsh weather or a forceful closure causing the hinges to move slightly.

How To Fix The Hinges

If your hinges are the problem with your UPVC window, then you’ll likely need to replace them – especially if the hinges are worn. Replacing them is certainly a two person job, as you’ll need someone to support the frame when you remove the hinges. This can be quite heavy so make sure the individual is prepared to support that weight.

To remove the hinges:

  • Loosen the hinges from the frame by unscrewing them and removing the screws holding the hinge in place.
  • The person helping you should try to hold the window in place as best as possible for a quick replacement.
  • Line the screws of the replacement hinge in place and tighten them to support the frame again.
  • You’ll need to do this for both sets of hinges.
  • Test the fit, and ensure the windows are opening and closing as normal.


If the hinge simply needs adjusting, then tighten/loosen the screws holding the hinge in place and test the fit to see if the UPVC window now closes effectively.

Problems With Window Sealant

Although less common, the seal around your window that’s made up of a rubber material can cause the issue. If it has warped, deteriorated, or become blocked with dirt or debris, then it can stop your window from closing.

How To Fix Rubber Seals

If it’s simply dirt or debris causing the issues, then a thorough clean with warm soapy water and a soft cloth will do the job. Don’t wipe too vigorously or you might warp the seal – pay special attention to the corners and gently remove any dirt or debris preventing the closure of the window.

However, if the seal has warped or deteriorated you may have a more complicated job on your hands. If it has simply warped, you might be able to gently ease it back into position. Try this in the first instance, but if it doesn’t work, then the seal will need to be replaced. This is also the case if it has deteriorated in such a way that it is no longer effective. To replace:

  • Use a utility knife to loosen the seal on both sides and remove.
  • Clean the gap thoroughly with a damp cloth.
  • Allow the gap to dry before attempting to replace it.
  • Apply the new sealant using a caulking gun – evenly applying the sealant the whole way round.
  • Leave to dry before checking if the window will close.


Problems With Handles

Similar to the locking mechanism, sometimes UPVC windows can have problems with the handle where they simply break and are unable to be used – here replacement is your best option.

How To Fix The Handle

All you’ll need to do here is remove the handle, take it to a hardware store to exact match it, and then replace it with a new one. The steps are simple enough:

  • Unscrew the old handle from the frame. You may need to remove a screw cap to access them.
  • Take it to a local hardware store for a replacement.
  • Simply screw the new one into place.


Problems With The Window Frame

A major issue causing your window to not close properly is window sagging – also a problem with certain types of door, too. This is usually caused by damp issues or improper installation, and may be seen more commonly in a bathroom window than any other in the house, but it’s still possible anywhere.

How To Fix Frames

If your window frame has sagged, you will almost certainly need professional help, as it may speak to structural issues with the window itself, and a repair or replacement may be necessary.

Either way, we would always recommend seeking the help of a professional if you notice your window sagging away from the frame at the top or bottom.

Still Not Fixed?

It may be that the fixes outlined today simply won’t work – if that’s the case, you’ll need to seek professional help. Contact a local window installer for assistance.


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