• Cracked/broken panes;
  • Binding during operation;
  • Failure to lock;
  • Hardware damaged/inoperable/out of adjustment;
  • Missing/stripped cranks;
  • Operator arm failure;
  • Moisture damage;
  • Sun damage;
  • Weather-stripping components


Tempered glass will be permanently marked as tempered- usually by etching- in a corner or along one edge.

Tempered glass is required where ALL OF THE FOLLOWING apply:

  • The glass is larger than 9 square feet;
  • The bottom edge of exposed glass is within 18 inches of the floor/walking surface;
  • The top edge of the glass is more than 36 inches above the floor/walking surface;
  • There is a walking surface within 36” horizontally from the edge of the glass;

Other locations:

  • Glass in a tub or shower where the bottom edge of the glass is less than 60 inches above the floor/walking surface;
  • Glass adjacent to a door where the nearest vertical edge is within 24” of the arc of the door and whose bottom edge is less than 60” from the floor or walking surface.
  • Glass in stairways, landings, and ramps when the walking surface is within 36” of the glass, and the bottom edge of the glass is less than 60” from the walking surface.


     I stopped into a glass place to ask about something for my truck and they mostly do residential and commercial windows. I asked him about failed window seals.
He said "Failed seals" isn't really an accurate description.
His explanation:
     Windows have breather tubes installed so that the pressure in the space between panes can adjust to changes in altitude when the windows are transported. These tubes are supposed to be cut/crimped when windows are installed but that doesn't always happen, and sometimes it's done poorly.
     He said some thermal pumping is natural as the window experiences day/night temperature cycling. The panes bow inward and outward with changes in temperature (like a bellows) and this action moves small amounts of moisture-laden air in and out of the space between panes.
     The aluminum strip around window perimeters between the panes covers silica beads that have desiccant properties... they absorb moisture from the air. When the silica become saturated, condensation will begin to form on the interior of the panes and then it's time to replace the window.
He said it's not uncommon to see some condensation near the upper corners while the window is still in good condition. To know the real condition of the window it needs to be monitored under different conditions.
    I said "You know we have inspectors all over the place recommending replacement when they see any condensation, and they're only onsite for a few hours".
    He shook his head and said "I know".
    This guy worked for Pella Windows for 9 years and is good friends with the CEO of Anderson Windows. He's been in the glass business all his life. I got the impression that he knew his stuff.
     Obviously, if you see condensation across a large portion of the window, or permanent hazing or etching of the glass, recommend replacement.