double glazing cracking

[JannyBee]

Hi
I've recently moved into a refurbished flat. since moving in 2 windows have spontaneously cracked. On the first one it started on the edge and worked it's way across the window. The second one hasn't gone all the way across.
What could have caused this? It wasn't bad removal men as it started after the move.

 

[crank39]

The basic answer is Thermal stress.

Take a read of this, it does a good job of explaining why it happens....

http://www.thewindowman.co.uk/explode.htm

 

[big-all]

another thought is settlement or movement
is there any cracks or signs off movement

 

[foxhole]

What type of window, seen sash windows crack after bodged fitting of lock , too long a screw was used to secure and it penetrated the frame and cracked window.

 

[JannyBee]

I was worrying that my landlord would insist that I had damaged the windows but the thermal theory sounds right. We had that really cold weather earlier this year and I had the heat up.

The windows are on opposite elevations and no signs on new paint of any distress on walls or ceiling.

I had thought that it was bad installation (as one window has internal condensation) and the cracks start from the edge of the windows. I just didn't think that would be much of a defence as the windows had been installed for some time.

Thank you again to everyone who responded.