The window is being stressed by changes in the wall geometry. It could be that the foundation is settling. Foundations move a bit when the soil gets really dry. Have you gone a long time with no rain?

Thanks Eric, No, we haven't had much rain this past summer. I've done alot of landscaping all around the house, so I've been watering. The foundation would settle even more in a house this old?

Terry

There's a lot of stress on that window that could have been caused by a window that was fit too tight or a major settling somewhere. I would have someone look at it right away cause it sounds dangerous. Anyone standing by that window can get hurt if the stress becomes too much for the window to bear. Good luck...

You're right, how could an old house have a foundation that's still settling? It could be an installation error made when the window was put in. Or, it could be that the remodeling done recently has caused the wall to change somehow, and this has changed the shape of the window frame. Do the windows open and close readily, or do they stick and drag?

The windows open and close just like they did before...readily. I talked to the guy Fri. night, who installed the bracing (the jacking up and bracing of floor joists) and the sheetrock. He said and I'm going to quote, "you don't know if during the installation or destruction, somebody hit the window. It just needed the cool air we've been having to make the crack show." Sooo...I said, you hit the window? He never answered me....I think that pretty much answered my question. Think so?

Terry your house I think is done settling. The interior wall changes won't effect the exterior windows load enough to cause any stress cracks in your window. I don't know where the others are coming from on this one. Your outside wall the window is in has the duty of bearing the load along with your header. In most cases as you've found the window is broken by your demolition crew or the neighbor kids playing baseball or golf!!! If there is any load on the window frame the sashes won't work and you'll see it bow. The chances of shattering are almost zero. The glass is made to stick to the spacer and not fall out of the unit. It will still break and fall out but some will stick inside. Here's what I do to check for a stress crack of hit. I have a big sharp hat pin from the old days. I run the pointed end in the crack and let it follow the line. If it was hit by something you will come to a chipped area. If you don't see anything visible there then it may be behind your glass stops which remove. These are thin pieces of vinyl that would show a visible smack on it from one of the trades. If it was cracked during installation it would have come to view within a year during the season changes. It would have also fogged up inside the glass during certain weather patterns. My money is on your Contractor or employeess!!!!

thanks guy, I really do believe my contractor did it. Now to find someone to replace the glass in both windows.

Terry