Any advice re a cracked glass window please?

chesca05

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Yesterday I noticed a crack radiating from the edge of the inside of my double glazed window (it's the end pane of a French door unit) which can hopefully be seen in the picture above. There has been no impact & after a bit of googling it looked to me that this is thermal stress crack...the window is south facing & the temperature fluctuates dramatically from freezing cold in the morning to red hot in the afternoon when the sun's out. I've contacted my letting agents who said they would contact the company that built the house as it is a fairly new build but they are denying that it's a stress crack and are putting the blame on me (this is from the pic as no-one has been out to see it). Can anyone give me any advice or know how i can prove I'm not to blame?

TheCyclingProgrammer

Conversely, how can they prove it was you?

There’s no obvious sign of impact damage to me but even if the window had been broken by impact, how would they be able to prove it was you and not kids throwing stones or some other form of vandalism?

This really isn’t your problem, it’s the landlord and letting agents. Let them argue the toss with the builder but make sure it gets fixed. It’s not a big job.

chesca05

The damage is to the inside pane so couldn't have been caused by anyone else. I have asked the agents to get a third party to inspect it and give their professional opinion. I've been really geeking up on different types of cracks and have put together a heap of information to support the fact that this isn't caused by an impact. Just have to wait and see what they come back with. Thanks

missile

I fail to understand how an inside pane of a double glazed unit would be subject to severe thermal stress?

Thermal stress cracks in windows are easy to identify because they start perpendicular to the glass edge. “It’s easy to identify a stress crack if you can see the edge of your glass,” he said. “The crack will extend about a half-inch straight away from the glass edge.”

I would suggest the nature of the damage to your window is consistent with accidental damage. There may be a manufacturing defect, e.g. a chip at the edge of the pane which would act as a stress raiser and slamming the door could cause the glass to crack.

Per your letting agreement, if it was your fault then you have to pay for the repair?

robin58

Looking at the picture it looks like the stress points are the at the right of unit edge as they radiate from there.

With Double glazed units, units can have stress points on the outer pane, the spacer framing and the inner pane. As they can all expand and contract differently.

It's a high possibility that the unit had slight chips to the edges of one of the pieces of glass when put in and as you suggested the frame has expanded and cooled sharply.

Add this to the possibility the outer frame has not been put in straight and square could have over stressed the unit with the chipped edge plus heat and contraction to make the pane crack.

My experience. Used to work in the glass industry and have made a few DG units in my time.

[Deleted User]

Hi,

easier to view this way,



Edit: Was door open and got a stone chip flung up to 'ping' the inside glass, but didn't spread until the door was pulled shut?

tonyh66

should that pane not be toughened glass?

Ruski

tonyh66 wrote: »

should that pane not be toughened glass?

Exactly what I was thinking!!??

chrisw

tonyh66 wrote: »

should that pane not be toughened glass?

Does the cracking not indicate it's laminated glass?

TheCyclingProgrammer

chesca05 wrote: »

The damage is to the inside pane so couldn't have been caused by anyone else.

Ah, that wasn't really clear when I looked at the photo on my phone, sorry.

phill99

Having battled with a customer on something similar, it could easily have been caused by an 'inclusion'. This is a minor manufacturing defect, often not seen by the naked eye, but weakens the glass and any slight movement can cause it to crack.


The damage seems to permeate from the very edge of the pane under the rubber gasket. I would suggest if you had hit the glass, it would not have been in this location, as you are more likely to hit it within the wider pain area.


I think you need to ask your agents to prove that it was you that caused the damage. And in terms of the builder denying liability : of course they will deny liability.