Distorted reflections on window glass

^woody^ said:
Have a search for Sheet 4.10 from the Glass and Glazing Federation. This details the specification for visual quality and the common issues and acceptability of them.

That last image does look particularly bad and unacceptable. I've seen better sheets of plastic on bus shelters.
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Thanks that’s really helpful. My thoughts exactly on the plastic finish…. It may be something to do with Brewster’s fringes having the document. I may contact the Federation to see if they can advise.
 
Lulusun said:
It may be something to do with Brewster’s fringes having the document
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Brewster's fringes have a different effect.

Looking back at your photos, if we take for example, the reflection of the roofline...

image20.png

We see one reflection being bowed upwards (blue) and a second reflection bowing downwards (red).
This is the phenomenon described in B2.4
Screenshot_20231007-214146_Adobe Acrobat.jpg

...and is what @Harry Bloomfield described in post #2

It may be interesting to know what altitude your property is, and where the sealed units were manufactured.
 
RandomGrinch said:
Brewster's fringes have a different effect.

Looking back at your photos, if we take for example, the reflection of the roofline...

View attachment 316244
We see one reflection being bowed upwards (blue) and a second reflection bowing downwards (red).
This is the phenomenon described in B2.4
View attachment 316245
...and is what @Harry Bloomfield described in post #2

It may be interesting to know what altitude your property is, and where the sealed units were manufactured.
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Nothing unusual - about 300ft above sea level and the sealed units were produced in Preston, I believe.
I don’t quite understand how the explanation from post #2 can be correct; surely if that were the case then all windows will appear distorted except on very rare occasions when the ambient pressure equals the pressure within the gap, which is not the case because most windows look straight (all of the time, as far as I have noticed) despite fluctuations in pressure. Unless you’re saying the pressure in my windows is wildly different from the normal bounds of ambient pressure in my location?
 
Lulusun said:
I don’t quite understand how the explanation from post #2 can be correct; surely if that were the case then all windows will appear distorted except on very rare occasions when the ambient pressure equals the pressure within the gap, which is not the case because most windows look straight
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Sealed units, despite there name are leaky. A best case leak rate is quoted as 1% per year.
Older units will have less differential pressure differences, than new ones.
 
Lulusun said:
Nothing unusual - about 300ft above sea level and the sealed units were produced in Preston, I believe.
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It doesn't really matter where they were produced, what matters is the prevailing weather conditions at the time they were produced. When your local weather conditions match, those at the time they were produced, they will be flat.
 
Harry Bloomfield said:
Exactly - the OP's panels are new.
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Ok so to make sure I understand, you’re saying all windows will likely have this distortion effect unless the ambient pressure happens to match that of the pressure inside the windows, but that with time this effect will reduce because of leaks which will enable older windows to equalise with ambient pressure more easily?
 
Lulusun said:
Ok so to make sure I understand, you’re saying all windows will likely have this distortion effect unless the ambient pressure happens to match that of the pressure inside the windows, but that with time this effect will reduce because of leaks which will enable older windows to equalise with ambient pressure more easily?
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Correct!
 
For a start , very very unlikely to be a vacuum , I think only two places make them with a vacuum and that's normally for Heritage reasons. Being Argon gas filled I can 100% guarantee not vacuum .
To me , it looks like cheap float glass, probably purchased in Europe at a cheaper price than from one of the UK manufacturers. The glass never seems to be of a similiar quality as UK glass, more brittle and harder to cut. As Harry is saying the atmospheric pressure within the sealed unit plant will have an affect on the quality ( and longevity ) of a sealed unit. I'm not sure where you stand with GGF regs , as they always state ' looking through the glass not at the glass ' but honestly I'd be changing them, I can guarantee the installer ( and manufacturer ) wouldn't accept those in their own property. That last one is absolutely awful.... it would look good in a listed period property though lol
 
I should clarify that the installer would have little to no control over the quality of the sealed units , and in truth the manufacturer wouldn't know until they were installed , as a quick ( and it is a quick if at all ) Inspection in a factory won't have spotted it
 
ronniecabers said:
I should clarify that the installer would have little to no control over the quality of the sealed units , and in truth the manufacturer wouldn't know until they were installed , as a quick ( and it is a quick if at all ) Inspection in a factory won't have spotted it
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Thanks. All the sealed units have these terrible distortions and he tried a sealed unit from another manufacturer that he had used on another job (it wasn’t the correct size so he just held it by hand while i had a look) and they had the same distortions. So I don’t know what the solution is.
 
That's odd that sealed units from an alternate supplier had same distortion. I would expect a small amount of distortion but that last picture almost looks like the Mirrors you get at the funfair
 
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