What causes condensation IN double glazing that has NO SEALS

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Hello everyone,

I would be grateful if anyone would answer the question: what actually causes the condensation inside double glazing where there are no seals present?

I have read that it's the seals that go that produces the moisture. However, with my windows there are no seals, the panes of DG are just inserted into and held by the wooden frames.

I would like my DG to last a while longer so I was wondering if the condensation in my windows has come about by excessive heat on very hot days, that is, the strong heat has damaged the window in some way where condensation is then the persistent result. If this is the case then I could put a covering on a couple of my downstairs windows to stop the heat on hotter days from causing the damage to the windows that are still presently condensation-free.

Thank you in advance for all who answer.
 
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Double glazing units are effectively sealed themselves....two panes of glass (typically) are separated by an aluminium frame, clean dry air is in the void between, and then the aluminium frames are sealed on the outside. When this seal fails, condensation is the result.
It doesn't really matter what window or door frame the DG unit is in - timber, alloy or uPVC, but the fitting method and design can prolong the life of the DG seal.
John :)
 
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Many thanks John.

I see now that I do have seals and mine have gone on a few panes.

Could you comment on whether I could prolong my DG, and stop further internal condensation in the windows that don't have damaged seals by putting up a covering over these windows to stop the hotter weather from causing the initial condensation.

Thanks again.

Paul.
 
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Personally I don't think you can, Paul.......the double glazed unit can look after itself, but it needs to be installed with a certain degree of sympathy.
In other words, see that there is no twist in the pane which could stress the seal, and make sure the unit doesn't sit in water.
DG units, when fitted to PVC frames, are held by double sided tape, and when retro fitted to timber frames need a thin layer of silicone on the back to allow for some movement. I fix the timber glass beads in with a layer of putty in a tube to keep them watertight.
Be aware, DG units don't carry anything like the guarantee they used to - some say that after 5 years they are on borrowed time.
I restored my house in 1986, and all the units have been replaced since.
John :)
 
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Thanks for your generous replies John.

The house I'm in is 19 years old now. The windows at the front of the house (south facing) had been replaced before I came here 2 years ago These windows are fine. The older ones at the back are the originals, so it's fair to say it's not surprising their on their way out. At present the panes that have gone are in rooms that don't matter so much. The kitchen window which is used constantly has just one of the 6 panes that is going. and it was this window I was mainly asking you about to see how long I can continue seeing out of it to a good degree before the panes need changing.

Interestingly, the wooden frames at the back (north facing) are still in good condition. This will mean there's no immediate need to change the whole window/s. I will probably let some time pass and then replace all the back windows in one go.
 
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Sealed units often fail because they sit in rain water due to poor fitting or because drain holes are blocked, the unit should sit on small rubber pads to keep it out of rain collecting in frame.
 
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Thank you for the replies.

I found the website helpful. And I'll check to see if rain water can get to beyond the surrounds.
 

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