What could be the cause of this glass crack in a window?
Mitsuko
| Posted in General Discussion on
I live in a rented apartment and have noticed a glass crack in a window, so I’m trying to figure out whether I damaged the glass or it somehow got damaged on its own (for example, by thermal stress), in order to decide how to talk to the landlord about it.
The crack is in the inner pane of a double-paned window and looks pretty unusual, unlike a “normal” glass crack. Here’s a photo (in which I put a piece of paper on the glass to make the camera focus on the glass): quZmL.jpg (905×2185) (imgur.com)
The photo was taken when the camera was oriented parallel to the window – that is, the line of sight was perpendicular to the window.
As you can see in this photo, the crack is an ideally straight line that goes exactly vertically, getting thinner towards the ends, and is about 15 cm long and 1 mm wide. The crack looks as if it were a long cavity filled with air or water, no matter the angle you look at it, so I’m unsure whether it’s really a crack or something else. And when I touch it with my finger, I don’t feel any surface irregularity whatsoever, so the damage seems to be entirely inside the glass. The crack is near the center of the window, so both ends of the crack are far from the frame.
I wouldn’t suspect myself of damaging the window if I hadn’t recently killed an insect on it with my finger. The impact of my finger was so mild that no one would ever expect any glass damage, and I didn’t see any crack appear when I killed the insect. Neither did I hear any crack sound. But the crack is pretty much where I killed the insect, and I noticed the crack about an hour after I killed the insect, so I’m at a loss as to whether the crack is due to that impact. I’ve never really paid attention to that window, so I can’t exclude that the crack was already there when I moved in.
My question: Based on what the crack looks like, can I exclude the possibility of it having been caused by that physical impact of my finger? Could a glass crack due to an impact look like this? What could have caused such a crack?
Replies
I have never seen a crack in glass look like that.
I have not seen a crack in window glass that didn’t end (or start) at an edge of glass.
Maybe a bullet hole with no extending crack to an edge.
Beats me.
Your crack!
It's possible that the glass just had an imperfection or weak spot right there. That one idea.
Another is that the glass broke because when it was installed it may have had what is called a claim chip.. or another thought is, it's sitting on metal maybe a screw head or end. There should be what is called setting blocks under the glass (2) one at each end of the glass . You have a unique situation. I'm betting that the crack extents all the way top to bottom you just can't see or tell that the cracked glass continues where is appears it stops. Every crack in glass starts somewhere but will end at the edge of the glass .. many times you won't see the full length of the crack until the glass is moved slightly and it then appears to continue to the edge. I'm betting that if the window sash has stops holding the glass in from falling out the it removed and inspected you will find something under the bottom edge be it a small nail head or some kind of chip in the glass. Truth be told no one will know unless or until the glass is removed and then whose to say what's the cause. Good luck and I suggest you leave the window alone unless you plan on footing the bill
I think you only injured the insect, which then cracked the glass in a desperate attempt to escape.
A window can crack like that due to argon depletion if the seal goes bad. The gas escapes so fast it creates a vacuum and breaks the glass. You may have dislodged the seal when you hit the bug on the window.
That’s a wacky crack, and I can’t imagine you caused it. Where is this apartment? Assuming from the buildings across the street that it’s not North America. Location and/or window brand might help identify common defects.
Based on the description and photo you provided, it's difficult to definitively determine the cause of the crack in the glass. However, it is possible that thermal stress may have caused the crack. This can occur when there are significant temperature differences between the interior and exterior of the glass, or between different parts of the glass. When the glass expands and contracts due to temperature changes, it can create stress that leads to cracks.
It's also possible that the crack was already present when you moved in and went unnoticed. Without additional information or examination, it's difficult to determine the exact cause of the crack. However, it's important to inform your landlord of the issue so they can take appropriate action to address it
Based on the description and photo you provided, it's difficult to definitively determine the cause of the crack. However, it's possible to speculate on some potential causes.
Firstly, it's worth noting that thermal stress can cause glass to crack, particularly in double-paned windows. If there was a temperature difference between the inner and outer panes of the window, this could have caused the crack to form. However, this is typically characterized by a jagged crack, rather than a perfectly straight line like the one you've described.
It's also possible that the crack was already there when you moved in and you just didn't notice it before. It's not uncommon for previous tenants or landlords to neglect to mention existing damage.
Regarding the impact of your finger, it's difficult to say for sure whether this could have caused the crack. If the impact was very mild, it seems less likely, but it's not impossible. A perfectly straight crack like the one you've described is unusual for an impact-related crack, but again, it's not impossible.