The House Detective by Barry Stone, Certified Home Inspector
Dear Barry: We recently installed two, large, double-pane windows in our living room, but we ran into a problem. The weather last night was very cold, and warm air from the floor register caused the glass to crack along the bottom edge of one window. It seems that we made a mistake installing the windows so close to the register. The windows are just a few inches above the floor. What do you think? Trudy
Dear Trudy: The apparent errors in this window installation are worse than you realize. Temperature differentials may indeed have caused the crack, although the cause might have been a flaw in the glass edge, as sometimes occurs when glass is roughly cut. There is, however, a bigger issue.
Windows that are larger than nine square feet and are within 18 inches of the floor must be made of tempered safety glass. The fact that your window cracked, instead of disintegrating into small shards, indicates that it is not safety glass. If someone were to walk into one of these windows, major injuries could result, and you could be liable for the costs of those injuries. My advice is to have these windows replaced by a professional glazing contractor.