To replace a cracked garage door window, wear gloves and eye protection, take off the trim, remove the broken pane, clean the frame, test-fit the new glass and secure the trim without overtightening. Clopay says most building codes call for tempered safety glass. Call a technician for full-view glass, heavy panes or a cracked panel.
Is a window pane a DIY job?
Often yes. A single cracked pane in a frame is a manageable task if you work carefully. It is not a good DIY job when the glass is part of a full-view aluminum door, when the pane is heavy or at the top of a tall door, or when the panel around the glass is cracked or bent.
Broken glass is the real risk. Close the door, keep people and pets away, and clear the floor under the window before you start.
Know which type you have
- Older doors (Hunker mentions before 2000): individual panes held in a frame with glazing compound and glazier's points.
- Newer doors: one long pane held between an inside and an outside frame that are screwed together.
- Check your owner's manual or the door label, because Clopay and other makers have their own frame designs.
Step by step
Measure the frame
Remove the trim and old glass to expose the frame. Clopay says to measure the width and height of the frame edge to edge, not just the old glass, and not to round the numbers.
Order the right glass
Ask for tempered or laminated safety glass. Clopay says most building codes require tempered safety glass in garage door windows, so check your local code before you buy.
Remove the broken pane
Wear thick gloves and eye protection. On a long-pane frame, take out the screws from the inside while someone holds the outside frame, as Hunker describes. Remove debris and old sealant.
Clean the frame
Scrape off old compound or sealant so the new pane sits flat.
Test-fit the new glass
Set it in without sealant first to confirm it sizes correctly.
Install and seal
Press the glass into place and secure the trim. Clopay says not to overtighten, because that can crack the glass.
Check the seals
Look for gaps or missed spots that could let in drafts or water, then run the door once by hand.
A heavier pane can change the door's weight. Clopay says spring adjustments should be left to professionals, so if the door feels different after the swap, do not adjust the springs yourself.
Quick answers
Can I replace just one garage door window?
Yes, on most doors a single pane or insert can be replaced. A long-pane frame holds the glass between two screwed frames, so the whole piece comes out together.
What kind of glass should a garage door window use?
Clopay says most building codes require tempered safety glass in garage door windows. Check your local code and your door maker's guidance before you buy.
How do I measure a garage door window for replacement?
Remove the trim and the old glass, then measure the frame width and height edge to edge. Clopay says to double-check and not to round the numbers.
Will new glass change the balance of my door?
It can, if the new pane is heavier. Clopay says spring adjustments should be left to professionals.
What to avoid
- Do not use ordinary window glass. It breaks into sharp pieces.
- Do not overtighten the trim or screws. It can crack the new pane.
- Do not work on the door while the opener can run. Unplug it or stay clear of the wall control.
- Do not lean on a cracked pane or a bent panel. If the frame is damaged, the panel may need repair.
When to call a technician
Call if the glass is part of a full-view aluminum or glass door, if the pane is large or heavy, if the door is out of balance after the swap, or if the panel itself is cracked. Hunker also notes that the newer long-pane type might make more sense to leave to a professional. A cracked window is a good moment for a 12-point safety inspection, which is $89 and checks the springs, cables, rollers, tracks, sensors and opener.
Emil Garage Doors repairs and installs garage doors across Southern California, including in Campbell, Monterey and Dinuba. Call (213) 340-4232 or use the estimate form on this page with a photo of the window if you can.
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