What caused this??

[BOBOT]

MIL sent this photo of her sliding glass door onto the deck. She has no idea what happened; discovered it in the morning after rising. I first thought it might be a stray bullet--she lives in a sort of rural part of CO. But she says the cracking is on the inside pane of the double-glazed door.

Any ideas?

 

[Jerry1]

given that there seems to be no impact location, I would say that either the door was open/closed to aggressively or that heat/cold deformed the frame enough that it created enough pressure to break the glass. As bad as it looks, that's how tempered glass breaks. It doesn't mean some major impact happened. Just enough pressure and that pane of glass is gone. It doesn't crack like normal glass.

 

[imoldernu]

We had the inside pane of a thremopane window shatter for no apparent reason.

Try this, for a possible explanation:

https://en.wikipedia.org/wiki/Spontaneous_glass_breakage

Check out "thermal stresses"

 

[splitwdw]

Could an animal hitting the door cause the problem?

 

[Winemaker]

If it is an Anderson window/door, I think the glass is under warranty for 20 years.

 

[MRG]

We had the inside pane of a thremopane window shatter for no apparent reason.

Try this, for a possible explanation:

https://en.wikipedia.org/wiki/Spontaneous_glass_breakage

Check out "thermal stresses"

+1
Seen it happen without any visible cause.

I have also see a full pony beer go through a door like that, surprise! That left a hole.

 

[Curmudgeon]

Tempered glass doesn't usually break, but when it does, it breaks ALL THE WAY.

 

[Animorph]

Looks like when I was drilling a hole in a sliding glass door frame. the drill suddenly made it through the metal frame, hit the glass before I could react (didn't even think it would extend that far into the frame), and my door looked just like the OP photo. Doesn't take much to shatter the whole pane.

 

[JPatrick]

We get frequent bird strikes on a big window we have, nothing broken yet, but the bigger ones really smack it. I think they are capable of breaking it.

 

[BOBOT]

Thanks for the responses, but again: this is the inside pane so no animal strikes (unless MIL went nuts in her sleep).
And I don't think the temperatures this year have been extreme there. The house is about 25 yrs old, & they've certainly had colder winters.

 

[MRG]

We get frequent bird strikes on a big window we have, nothing broken yet, but the bigger ones really smack it. I think they are capable of breaking it.

We lived 10 years in a place that always had birdstrikes. Never lost any of our old glass to them, no matter how hard it sounds. We got hit from hummingbirds to owls(he made a really big thump) and never lost windows to birds.

 

[Dash man]

I'll believe the MIL theory. It makes the most sense.

 

[samclem]

Thanks for the responses, but again: this is the inside pane so no animal strikes (unless MIL went nuts in her sleep).
And I don't think the temperatures this year have been extreme there. The house is about 25 yrs old, & they've certainly had colder winters.

Maybe settling of the house > racking of the frame> pressure on the glass (and the inside piece just happened to be under slightly more pressure due to size/position of the glass in the frame, etc). Are there cracks in the interior or exterior wall, or the foundation/slab, that might give a clue? Was the door binding in the frame? Are the measurements corner-to-corner of the outer doorframe identical? It's a rare house that stays square over time.

 

[JPatrick]

We lived 10 years in a place that always had birdstrikes. Never lost any of our old glass to them, no matter how hard it sounds. We got hit from hummingbirds to owls(he made a really big thump) and never lost windows to birds.

Yup, the guys who replaced our window said they have seen cases of damaged windows from bird strikes. Perhaps in those cases the window had prior damage and the bird dealt the final blow.

 

[MRG]

Yup, the guys who replaced our window said they have seen cases of damaged windows from bird strikes. Perhaps in those cases the window had prior damage and the bird dealt the final blow.

Wow big a $$ bird. Likely what you think. Something has to take the window out.

Back in the '70s I was sitting there and one of the doors went crackling and poof! Shattered! Other people saw it too.

 

[BOBOT]

Maybe settling of the house > racking of the frame> pressure on the glass (and the inside piece just happened to be under slightly more pressure due to size/position of the glass in the frame, etc). Are there cracks in the interior or exterior wall, or the foundation/slab, that might give a clue? Was the door binding in the frame? Are the measurements corner-to-corner of the outer doorframe identical? It's a rare house that stays square over time.

There were settling issues years ago, but they were successfully
addressed by the contractor. There really haven't been obvious issues that point to this.

Again, folks .. this is inside.., no bird strikes.

 

[samclem]

Again, folks .. this is inside.., no bird strikes.

Does MIL own a bird? A big 'un?

 

[Another Reader]

I had this happen, but it was the outside pane on a sliding door. I was sitting nearby and heard a loud noise as the glass cracked. I looked up to see the entire pane in a similar pattern as the picture. There was no impact on the glass, it just cracked. The glass guy said sometimes internal temperature differences stress the glass over time.

 

[6miths]

We get frequent bird strikes on a big window we have, nothing broken yet, but the bigger ones really smack it. I think they are capable of breaking it.

If you go to the bird store or look online and find transparent decals that reflect UV light that the birds can see and won't fly into your windows. Humans can't really see them.

https://www.amazon.com/Window-Alert...1488690993&sr=8-4&keywords=bird+window+decals

 

[eytonxav]

I've seen that happen to an outside pane during extreme drops in temperature, but on the inside, possibly some distortion has occurred in the doors frame that stressed the glass.