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Why Is My uPVC Window Not Closing Properly?

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I've been writing on DenGarden for over 5 years and have over 25 years of experience working in the window and door trade.

Is your uPVC window not closing flush? This article will help you fix this pesky problem!

Is your uPVC window not closing flush? This article will help you fix this pesky problem!

How to Check Problems in Your uPVC Windows

The most common problem with uPVC windows is that the sash won't close properly against the seal, which means you will lose money when the heat escapes outside. The problem is caused either by the lock, the hinges, or a dropped sash.

Check Hinges for Gaps in Windows

Close your sash and check the hinge side. If there is a gap between the sash and the frame on the hinge side, then it is your hinges. All that is wrong is that your hinges are wearing down and not pulling the sash in tight against the frame anymore. A new pair of hinges is needed. It only takes a few minutes and is not a big job. Most people would be able to do this job themselves, and most window companies will do it for you.

Gap in window where hinge won't close the sash fully.

Gap in window where hinge won't close the sash fully.

Check Lock

Close your sash, and on the inside, slide a credit card between the sash and the frame. The card should fit tight and shouldn't be easy to move around. If not, then you more than likely are getting a draft. All that is needed here is a small adjustment to your lock and it will tighten up the seal. Almost anyone would be able to do this job; all that is needed is a set of Allen keys.

Check If Sash Has Dropped

This problem affects windows that have a side-swing opening, the type that opens like a door. Close your sash and look at the top corner above the handle. Move slightly; if you can see daylight, that means the sash has dropped.

Also, check that the sash is fitting equally with the frame. If it has shifted down at the handle side, then your sash may be dropping. Most sashes will drop a bit without affecting the overall performance of the window, but if it keeps dropping, that is when the problems start.

Espag lock showing the cams which can be adjusted to tighten the seal.

Espag lock showing the cams which can be adjusted to tighten the seal.

Check the seal with a credit card. It should fit tight and be hard to move.

Check the seal with a credit card. It should fit tight and be hard to move.

How to Adjust uPVC Windows Not Closing Properly

If you want to have a go at fixing any of these problems yourself, below is a guide to help you get it sorted.

How to Fix uPVC Window Hinges:

  1. Unscrew the hinges from the frame and lift the sash out.
  2. Have a look at the sash and the way the old hinges are fixed to it.
  3. Unscrew the old hinges and put the new ones in the same place.
  4. Place the sash back into the frame and screw the hinges back onto the frame.
  5. Check that it is opening and closing.

How to Fix uPVC Window Locks:

Adjusting the lock will only take a minute, and all that is needed is an Allen key.

  1. Open the window and look at the cams: these are the parts that move up and down when you move the handle.
  2. These can be turned with an Allen key. Turn them one way and it tightens the sash against the seal. Turn them the other way and it loosens them.

How to Fix a Dropped Sash in a uPVC Window:

  1. Take out the glass, then close your sash and make sure your sash is lined up.
  2. Now put your glass back in and pack it right around with plastic packers so that there is no movement between the glass and the sash. If you don't have plastic packers, you can get them at any company that makes windows. They are very cheap to buy. The chances are there is not enough of them in your sash from day one and that is why your sash dropped.
  3. To help prolong the life of your Espag locks and hinges, especially if you are living near the sea, rub grease onto them. This will keep the air from harming them, stop corrosion, and slow down wear and tear. As for the dropped sash, there is nothing you can do about this until it happens, as this happens due to the glass being fitted badly.

Feel free to ask any questions by posting them in the comment box below.

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This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

Questions & Answers

Question: I have adjusted a small upvc window, so it closes tighter on the lock side, but how do I adjust the window so it closes tighter on the hinge side, as I can clearly see that the rubber seal is barely compressed?