bay window, water inside double glazed unit, repair seals or replace?

Posted 2nd Jan 2023

Another day another problem. We have a 1930s semi with a bay window top and bottom. The windows were in when we moved in and are double glazed but fairly old. i would hazard a guess at 15-20 years. The upstairs bay window has developed moisture inside the double glazed part. I assumed it would be a failed seal. I have researched the seals and after much faff, determined a specific E type gasket seal that is used on the unit. My plan is to remove the seals, attempt to dry the moisture with a hairdryer or demumidifier, replace with new seals and live happlily ever after

My dad has just thrown a spanner in the works and explained the double glazed unit would be air filled or something and that newer ones have argon gas or something in them so the unit might be no good anyway. i know nothing of double glazed windows but am fairly happy to do my reaearch and attempt a fix.

Can any windows experts give some pointers or guidance on this?

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2nd Jan
If the frames are still ok get a price from a local double glazing company to just replace the sealed unit. You may well find though now that one has gone several of the others will also.
2nd Jan
The seal you are referring to has nothing to do with the double glazed unit. All those seals do is seal the double glazed unit to the frame.
The unit has gone and needs replacing. Fairly cheap and easy to do yourself if you're happy to remove and replace the beading.

If the beading is outside though, the frames are really old and likely be better off being replaced.
2nd Jan
Try: cloudy2clearwindows.co.uk/
2nd Jan
The units themselves are sealed (with some sort of sticky tape) and then sealed into the frame.
As far as I can see, you have researched the seal into the frame, but not the unit seal, which I believe are fairly impossible to fix.
2nd Jan
Replace the sealed unit. You'll have to remove the beading, then look at the window to see the thickness of each piece of glass, plus thickness of the internal spacer between the glass. Armed with that you can order a unit online.
All this easy on ground floor. Plus the postage for one sealed unit can be pricey unless you choose a firm that will deliver in about 6 weeks when they've enough other orders for your area.
Bearing that in mind probably best to ask a local firm to replace the sealed unit for you.
Changing the entire window ill be expensive for a bay window as it's really 3 windows. Then you'll want to consider doing them all so they all match!
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2nd Jan
It appears that condensation has built up on glass and dripped to the bottom, which has then leaked through the seal and caused the moisture. If I look inside the unit itself, I can see a small puddle of water has formed on the bottom inside the actual double glazed unit.
2nd Jan
The double glazed unit is blown and needs replacing as you have been advised correctly above. The condensation on the outside and outer seals you can see are irrelevant. You cant see the double glazing seals as they are hidden behind the beading at the edge of the glass within the frame.

Have a look on youtube about replacing a glazing unit and see if you are happy to do it yourself. If not, get a glazing company in and replace the glass unit.

If you unit is externally beaded then you would be better off getting a whole new window as in theory, someone could remove the glass from outside and gain entry whilst you are out although despite what insurance companies say, this rarely happens in reality.

Got a picture- close up of issue including frame edge and double glazing water maybe? (edited)
3rd Jan
The glass pane unit has failed.
There is a hot sealant that is used to close the gap between the two sheets of glass. Over time it can deteriorate and then allow air in. The air will have moisture which then condensates on the glass and water fills the internal void. Need a new glass sealed unit there is no easy fix only replace the whole glass section.

(edited)