Magically broken windows

[chrisprickett]

I've gotten about 10-15 calls in the last year from clients complaining about windows spontaneously breaking. These are all in the same community, of about 8,000 homes, 7 years old or newer. All windows (and sliders) are double pane. Some are tempered, some not. Some are low-E, some are tinted, none are gas filled. In almost all cases it is the interior pane that is breaking. And in almost every case homeowner responsibility was ruled out.

My first thoughts were:

-the windows were tweaked during installation and the stress caused them to crack over time

-might be heat related

-A header settled causing stress

Most of these I ruled out. Any other theories?

[Jim Katen]

Originally posted by chrisprickett

. . . My first thoughts were:

-the windows were tweaked during installation and the stress caused them to crack over time

Unlikely. In my experience, if glass is going to crack from stress, it cracks immediately. Otherwise, it slowly accommodates the stress and becomes less likely to crack over time.

-might be heat related

Does it generally happen on the south side in summer? If not, I'd rule out heat.

-A header settled causing stress

That was my first thought. Or settling foundations. I see it occasionally in houses that are slowly sliding down hillsides.

Most of these I ruled out. Any other theories?

Are all the windows made by the same manufacturer?

If not, are all the manufacturers using glass from the same supplier?

- Jim Katen, Oregon

[kurt]

I had something like this that was a combination of heat & mfg. defect.

There were metal glazing clips holding the glass in the sash, sun on the south side of the building caused the windows to heat up, and the expansion made the little metal thingy blow up the window.

Or something like that; we never figured it out for sure, because all the windows got yanked & replaced before we could figure it out all the way.

[MelB]

I have the exact same problem in my house. The first one was after I hooked up my new surround sound. The next day, I noticed the interior pane of my pricey Gilkey window was smashed. I thought 'Wow what a subwoofer!' A couple months later, two windows on the upper level, one on each side of the house, spontaneously smashed themselves. Gilkey replaced all three under warranty, and told me that they had never heard of it. The installer though, told me that it happens on occasion due to a design problem in the window. He wouldn't or couldn't elaborate on it. It has happened at night, and during the day, in winter and a warm spring day, so the weather and sun didn't seem to play a role. Hope this helps.

[chicago]

Chris I think Kurt might be on to something, you can probably forget about the header idea since some of these windows are sliders it's doubtful. You never mentioned what the framing material was. If it's wood than what Kurt is referring to is the window points. Therefore one clue might be in the glazing which basically acts as a shock absorber while the points hold the glass in place. Also a lousy glass cutting job can set up a small fractures which will magnify over time.[:-graduat

[chrisprickett]

Thanks for all the input.

They are metal frame windows, but do have clips (not points) holding them.

The heat thing doesn't seem plausible because some are under covered patios and/or North exposure.

All are made by the same company (Atrium- a local company) and are builder grade. The lousy cutting job could be a winner. I could see there being a problem with the factory's quality control. Jim- If the windows are chipped during cutting, would they be more likely to crack over time, or would they accomodate as with your explanation regarding stress?

[chicago]

Chris I know you directed your question towards jim, however after many years of replacing glass panes and window frames I can tell you with certainty that any small fracture whatsoever will eventually crack the entire pane. Just put your foot on something ice and watch the cracks spread as you apply pressure with your foot. Although I suppose in Arizona this might be difficult to achieve.