uPVC Sash Windows not closing properly

1 May 2021
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United Kingdom

I've got an issue with a uPVC sash window that won't lock on one side. I think the issue is that the two windows aren't lining up: the top window is lower on one side which means the lock on this side doesn't work.

Has anyone else had this problem before? Is it something for a professional or something I could fix myself?

Any tips or advice would be much appreciated!



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Firstly check around the springs ( white tubes ) on either side of the sash , check nothing is physically stopping the sliding motion. The next thing would be to check that the sash is sitting in the ' pivot foot ' correctly , this is the plastic piece the spring connects to , and then a metal bar locates in it from the bottom of the sash also. It is very likely that the nylon ' pivot foot ' has worn/broken stopping the sash from sitting level. check these areas first
Thanks so much for your reply. I've taken a look at the areas you've suggested and can't see anything obvious (to me) that's blocking or stopping things moving. I've attached some photos of the area's you suggested looking at. Is there anything visibly worn or blocking the sash as far as you can see?

Thanks again,


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the very fact you can tilt the windows in rules out the ' pivot foot '. as normally it falls out of the ' foot ' when tilted in . next question is , is it the top or bottom sash that is stopping the lining up? If top push it up, and hold it, and see how level it is with the top of the frame, it might be a weakened spring, or a bowed frame ( but unlikely to be this to be honest , but I have seen it )
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Ah, I think you're right - it must be the top sash. The top sash doesn't seem to move at all, up or down. On other sash windows in the house the top sash does slide down so I'm wondering if there's something in place to intentionally stop it sliding down. Any idea if this is likely? If I could slide it downwards I might be able to inspect the spring and see if it's something I can fix.

Thanks again,



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OK, that's a start , so we know where we are looking.

The top sash doesn't move at all? Neither up or down? In which case , first thing to try is spraying a lubricant, such as wd40 , up the side of the top sash, ideally one of the cans with a straw nozzle, to try and soak the spring. If there is nothing physical you can see stopping that top sash moving then it is more than likely a seized spring. Leave the lubricant to work for 10/15 mins and see if there is any movement...if it does start to move , give it another squirt and then try again, if it frees up completely then give the spring a good dose of lubricant and work the sash up and down a few times take sure it is working
From looking at your pictures the top sash has a thumb pull in the centre, so I'm assuming it is supposed to move , if it's not then it will be screwed into the outer frame and would require the glass to be removed to check

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