Mysterious Cracked Internal Window Pane

[Tozzy]

Hi,

After waking up, I got out of bed to open my curtains and discovered a very long crack running the length of my window on the inside pane (the window is double glazed). I thought someone had fallen against it, but nobody ever enters my room. Here's some pictures:

Diagram of the crack:

There is a radiator infront of the window so you think this could have caused the problem? The window has been in for 7 years now and never had any problems.

Cheers.

 

[steveb1964]

i had the same in the bathroom a couple of years ago and the guy who swapped it said it can happen when it's very cold??

 

[Tozzy]

i had the same in the bathroom a couple of years ago and the guy who swapped it said it can happen when it's very cold??

But it's cold every year though or does it take about 7 years in order for it to happen?

By the way, do you know much it would cost to get it replaced (cost of unit and paying for it to be fitted)? I am not attempting this one .

 

[steveb1964]

here is an extract from the web which sounds like what has happened to you. also when the crack is all the way along the longest side this is also a result of the below info

This sometimes quite shocking occurrence of double glazed sealed units exploding most often happens in the U.K. between around late October, and early February, but mostly in late December - middle January.

When an inner pane in a sealed unit is the one to suffer breakage, this happens when the inner glass is warmed from the heating in the home, and the outer pane of a double glazed sealed unit is cold from a drop in outside temperatures. When an outer pane is the one to suffer breakage this happens when a cold outer pane is warmed quickly by the Sunlight bearing on it. The pane of glass subjected to the thermal stress cannot cope beyond a certain amount of deflection, and it will suddenly crack along the whole length of the unit, always along the long length, or it can suddenly shatter altogether.

Other contributing factors to double glazed sealed units breaking in this way can be: (1) Very high atmospheric pressure at the time and (2) An 'as manufactured' original high inbuilt negative pressure within the sealed unit. (3) One sealed unit laboratory recreated the effect of the glass surface tension being damaged by being scratched when the lead/coloured film/bevels were being cut around with a blade. If the glass is scratched in this way during manufacture it can be a weak point when the glass is under stress and deflection.

It cost me £75 to get it replaced, it is just over 3ft wide and has the autumn leave pattern in it as it's a bathroom window

 

[Tozzy]

Some great info there! Sounds exactly like what has happened. Ok, I'll get my mate to fix it.

Bluddy double glazing eh!