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How to Install New Glass Garage Door Windows

Making garage door windows from plexiglas sheets is a cost effective alternative to glass.

Making garage door windows from plexiglas sheets is a cost effective alternative to glass.

There are so many ways to accidentally break a garage door window -- especially if you have kids -- that it is almost inevitable that you’ll have to replace at least one in your lifetime. If you’ve never attempted something like this before, then you’ve found the right place. Here, we’ll give you a list of all of the necessary tools and a comprehensive guide that will take you from beginning to end, as well as answer questions about the most common problems that you might run into during installation. If you’re ready, let’s get you started making windows for your garage door.

Materials List

You may or may not need every item on this list depending on the way your windows are secured, but it never hurts to have them handy just in case.

  • Measuring Tape
  • Replacement window(s)
  • Work Gloves
  • Plastic Bucket
  • Putty Knife
  • Caulk
  • Liquid Cement or Wood Putty
  • Phillips Head Screwdriver
  • Hammer
  • Finishing Nails

Removing an Old Garage Door Window

Having a broken window on the garage door means that there are sharp edges at a level that most people can reach and may cause them to cut themselves accidentally. Getting rid of the broken glass is a priority. Steel and wooden doors use different methods to secure the window in the frame (and depending on the age of the door wooden fastening techniques may also be different), leading to several possible methods for removal. Each of these is discussed below.

To remove the broken window first put on your work gloves. Once you have done this, you can remove the lip that holds the window in place. The lip will either be held down with screws, finishing nails or caulking. If it is held in with screws (this is the case with most steel doors), use your Philips head screwdriver to remove them. In a wooden door, there may be finishing nails, staples or wood glue holding the lip in place. In a case like this, use the putty knife to pry the lip up and remove it. Be careful when removing the lip as the broken glass may fall out and possibly cut you. A safe, but slower, method is to loosen the lip and then remove the large pieces of glass by wiggling them out of the frame. Dispose of all of these glass shards in a glass bucket (or suitable trash container).

Finding a Replacement Garage Window

Most hardware stores will offer glass or Plexiglas cutting services, so finding a new window should be quite easy. Measure out your window frame with a tape measure -- measure it twice because once a piece of glass is cut it is very hard to adjust the size in small increments. Call the local hardware or home improvement store to get price quotes for the material you want to use. If you have children, you may want to go with the more forgiving Plexiglas.


What if my securing hardware gets lost or breaks?

If you lose your hardware or if the securing lip breaks, you will need to purchase a replacement. Most garage door models will have manufacturer’s sticker in either the bottom left hand panel or top right hand panel of the door. Once you have this information you can try a home improvement store or call the manufacturer directly for a replacement.

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What if I can’t remove the securing lip?

A stuck security lip is usually caused by adhesive cement or wood glue. Cutting the adhesive away with a razor blade or using a chemical solvent can loosen the adhesive and free the lip.

How do I make sure the replacement window will fit in the frame?

Measure the frame opening and subtract 1/8 inch from both measurements. This will assure the window fits, while still being held in the frame. Any possible drafts can be eliminated with caulking.

What thickness is replacement glass?

The thickness of garage windows varies by door model and age. To make sure your replacement window fits, measure the thickness of a broken piece of the original window and buy a piece at the same thickness.

What is the difference between Plexiglas and Glass replacement windows?

Plexiglas is a much more flexible than traditional glass panel. It will withstand several blows that would shatter a standard glass replacement. The downside to Plexi is that it will scratch more easily than glass.

Installing a Replacement Garage Door Window

To install the new garage door window, first you will have to prep the frame. Scrape the frame area with a putty knife to remove any residual glass fragments. Fit the new window into the frame and secure it with a bead of caulk. The caulk will hold it in place temporarily until the lip is secured -- it will also act as a weatherproofing seal to stop air leakage. Once the caulk has set for five minutes, install the bottom lip with the same hardware that you initially removed. Finish reinstalling the other three lip pieces. For a steel door, a small bead of liquid cement can be used to help secure the lip in place; for a wooden door use wood putty.

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