Double glazed broken glass window above door

[cherriepie]

I have a query..... I woke up this morning to a loud bang, not knowing what it was I looked around the house, Couldn't find what caused it.......A few hours later a friend called round and noticed bits of glass on my front doorstep outside, looking up we noticed the glass panel above the front door which is frosted double glazed was all shattered into big shards(seems this was the bang I heard) although the inner panel is ok. My question is... can this type of glass just give way for no reason, as if under pressure? I don't think it was smashed maliciously because it is shielded by a canopy and a good aim would be needed

[tzijlstra]

I would think it is incredibly rare for a glass pane to crack without any form of sudden pressure applied. Could it be that you live on a road with pebbles (like the ones from potholes) and one shot out from under a car? I once got a dent in my car that way (the pebble missed me by about a meter, was not impressed!)

[cherriepie]

We live on a dual carriageway which is heavy with traffic but quite a distance away from the road so I find it hard to believe it could be a pebble.

[Fogey]

The simplest explanation is that something hit it, - some sod threw something or perhaps a bird hit it with enough force to break the glass.

 

I have heard that it is not completely unknown though for windows to be structural in the opening (the frame acts as the lintel). So if you have had the window replaced with something that can't support the wall above the frame sags and the glass eventually breaks under the pressure as the load gets transferred to it. It could be that if you have some kind of arch over the opening it might have settled a bit putting pressure on the frame and glass. In either of these I would perhaps expect to see some evidence of cracking in the wall above or around the opening assuming it is a masonry wall. I would also expect it to affect both panes of glass.

 

If you think it is a real possibility that there is a structural issue then you should call building control at the council and ask for their advice.

[BIGDINNERS]

If you heard it, then the most obvious reason is someone has throw something at it,bearing in mind its under a canapy.

If a bird had hit it with enough force to break the window,the bird would break its neck and would be lying on the ground in the immediate area.

 

I see loads of bird strikes,doing my job,but I've never seen one break a window

[Blade73]

A similar thing happened to me a few years ago around this time of year. My neighbour fits double glazing and he said occasionally the glass can have a flaw in it and with the hot and cold extremes (ie freezing outside and heating on inside) it can cause it to crack, when mine did it sounded like a gunshot!

[Redyam]

Surely if someone had thrown something at it, the force that caused the front panel to break would have also broken the internal panel, and it would have smashed inwards. The fact that it smashed and fell outside suggests a different reason.