AliG

What happened to this window?

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My wife found a crack in a window today.

 

It is the middle and inside pane of a 3G window.

 

Looks like some kind of stress in the frame to me. Should this be covered by the warranty?

 

 

IMG_0625.jpeg

Edited by AliG
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BRE have written a report about that https://www.bre.co.uk/page.jsp?id=3112

 

"In the UK, glazing that faces south or west will generally become warmer than glazing facing east or north. South or west facing glazing is at greater risk of thermal breakage, which occurs when an area of the glass becomes warm but is adjacent to an area that remains cooler. The warmer part of the pane expands while the cooler area does not. This restrains the expansion of the warmer area which is therefore subjected to tensile stresses. If the difference in temperature between the two areas is sufficiently large, a fracture in the glass will occur. "

Edited by Triassic

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toughened glass is the usual answer

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I did wonder if the recent heat might have caused it.

 

As the units came already glazed then I think this would be the supplier's responsibility.

Edited by AliG

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1 minute ago, AliG said:

I did wonder if the recent heat might have caused it.

 

As the units came already glazed then I think this would be the suppliers responsibility.

 

They probably thought there was no chance of that happening in Scotland ;)

 

 

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When I got double glazing in the flat, a pane cracked the next day. Was replaced foc. Parents recently got triple glazing and oddly, one pane cracked too (north facing). It was replaced. Unless there is sign of physical damage id fully expect it to be warranted. 

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It happened to us with a small Velux roof window. Fortunately I wasn't underneath it when the glass broke as the broken shards of glass came down onto the seat I normally use. The glass was normal plate glass when it should really have been toughened.  

 

A Google search showed that Velux were (still are) offering to make repairs for free even though the window was about 15 years old. They ended repairing the one that broke and changed the glass in another similar one. The problem only occurs with their smaller roof windows and was caused by gas escaping from between the 2 panes of glass.

 

Edit:

I found the Velux info:

"The pane codes affected are only those with the reference 00UE, 59 or 34, in combination with the number 8 or the letter Y. The size of the pane is 39cm/15.5 inches or less. These panes were produced and sold between 1997 and 2003."

Edited by Ian

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Happened to one of our bedroom windows, about 6 months or so after it was fitted.  The inner pane of the triple glazing cracked just like that.  Munster came out and replaced it under warranty with no hassle and it's been fine since.  The window faces east, so only sees the sun in the morning.  The glazing unit was a Saint Gobain 3G argon filled unit, with a relatively wide gap between panes of 20mm (it was a 4-20-4-20-4 unit).

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They glass is 4-20-4-18-6.4 toughened - clear - laminated so the middle pane is the clear glass. I assume that the laminated is on the inside as windows are normally specified from the outside.

 

Curiously the spec seems to say that the windows have the laminated glass on the outside, but the patio doors like these have the laminated glass on the inside.

Edited by AliG

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You might be unlucky and have an "NiS", nickel sulphide inclusion issue. I know of at least one offfice block in London that ended up replacing every panel. It made the news after a couple fell out!

 

You can also get cracking like that stemming from a small "shell" on one edge.

 

And of course the frame being stressed by building movement is another possibility. 

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My Internorm windows are Triple 48 coated clear glass - glass spec is 22b.2(laminated)/16Ar/4/18Ar/B22.2(laminated)

 

I am still investigating the film and they are getting some thermal calcs from the manufacturer.  One film supplier told me not to have film on these windows another says its fine.  Any help please I dont want cracked glass. I dont understand the glass spec I just asked for laminated for security

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