Q: Is it required to have tempered glass in patio windows? The home inspector’s report said they needed to be replaced.
A: In my state, the building codes require tempered glazing in “hazardous locations.” You should check with your local or state building official before considering expensive repairs or replacement.
The International Residential Code section R308.4 requires tempered glazing in all glass sliding doors, bifold doors, swinging doors, shower doors and storm doors. Sidelight glazing for all doors under certain conditions need to be tempered. Most doors sold in my area must be tempered glass, and I rarely find any problems with door glazing.
Where I do find problems is in windows that are required for safety reasons to meet all of the following criteria:
1. Any window with more than 9 square feet of glass in a single panel (a double hung window is not a single panel);
2. The bottom of the glass is 18 inches or closer to the floor and the top edge is more than 36 inches above the floor;
3. There is a 3-foot walking area near the glass (this can be on either side of the window);
4. All glazing in a bathroom that is within 60 inches vertically of a standing or walking surface. This would include a shower or a tub drain.
I occasionally find homes that do not meet these safety standards and, with possibly thousands of dollars in replacement costs at risk, considerations have to be made on how to proceed.
If you have large windows in your home and you want to find out if they are tempered, look for a “temper” mark that is etched in between the two panes of glass. The mark is usually in a corner of the glass and may be difficult to find unless you use a flashlight shined at an angle or use a magnifying glass and search all four corners of the glass. Be aware that some manufacturers mark the glass with their seal, company name or other information. If the word “tempered” is not found and the window is in a restricted area, the glass should be considered for replacement. The glazings in doors are similarly marked.