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Replacing Window Glass

A Broken Window: You Can Fix It Yourself
A stray fly ball, a moment of temper or simple cloddishness can easily lead to a broken window. If the broken pane is large, don't do it yourself—handling large sections of glass is a major calamity waiting to happen, so bother to hire someone to come out and replace it. If the job involves a standard-size or smaller pane, however, you can do it yourself with a pair of nice, thick leather work gloves, protective eyewear and extreme caution. Wear thick pants, a heavy long-sleeved shirt and shoes.


What You'll Need:

  • Replacement glass
  • A sharp wood chisel
  • A box or belt sander
  • A glass cutter
  • A metal straightedge
  • Grooved pliers
  • A putty knife
  • A large carpet remnant
  • Kerosene
  • Glazing putty
  • Glazier's points
  • A small round dowel (a broom handle works fine)
  • A ladder (if you're working on a second-floor window)

Tip: The worst and most dangerous element of this task is cutting the glass. If you feel even remotely intimidated by the job (and there's no shame in admitting it), take the dimensions of the window opening to a hardware or home improvement store that has an industrial glasscutter and let them do it for you.

Once you have all your items assembled, you're ready to get started.


Put on your leather gloves and protective goggles before you begin. From the inside, tape newspaper or cardboard to the window frame to prevent glass from falling inward. Now move to the outside. If you're fixing a window on the second floor, you'll need a ladder. Start by removing the larger pieces of broken glass with gloved hands. If Glazier's points were used, yank them out with pliers. Remove all remaining glass with pliers or use a chisel to chip them out (you ARE wearing your goggles, right?). Discard the shards and fragments immediately. Once all the glass is gone, remove the newspaper. Clean and sand the wood sash and coat it with high-quality wood sealant. Back inside, examine the floor for glass that may have fallen past the newspaper and vacuum the area thoroughly, using a nozzle to lift any glass fragments away from baseboards, carpet, etc.
Tip: If possible, place your trashcan next to you to receive glass pieces as you remove them. If you need to transport glass, wrap it in several layers of newspaper and, if necessary, keep it wrapped and break it with a hammer into pieces small enough to fit into your trash receptacle. Make sure you inform family members NOT to shove trash down on top of your discarded glass.

2. Have your local hardware or home improvement store cut a piece of glass to fit the size of the opening. If you're doing it yourself, here's how: measure the opening and mark your replacement glass to be 1/8 of an inch shorter and narrower than your measurements (for example, if you window opening measures 25" x 25", you should draw out a square measuring 24 7/8" by 24 7/8"). If the replacement piece has good edges, measure from the top and one side to save cutting. A grease pencil or laundry marker will make the most obvious marks. Place the glass on top of a carpet remnant on your workstation or clean garage floor. Dip your glasscutter wheel in kerosene and cut along your lines, using a straightedge as a guide. Make your cuts as deep as possible.
3. Next, slide a small dowel (a round wood broom handle is fine), between your glass and the carpet so it is situated beneath one of your lines. Press both sides down gently until the glass snaps along the edge. Do the same with the other scored edge.
4. From the outside of the window use your putty knife and your fingers to make a ¼ inch thick tube of glazing putty and install it all the way around the opening to make a seat for the new pane.
5. Back inside, position the new pane in place, pushing it gently into the putty. If excess putty oozes around the edges, remove it. Install two Glazier's points for every 4 inches of glass all the way around the frame, pushing them in with a putty knife, screwdriver or trowel.
6. Make another ¼ inch thick tube of putty and apply it all the way around the inside edges, smoothing it as you go. Use the flat edge of your putty knife to create a nice smooth seal line. If the putty sticks, lubricate your knife with linseed oil and go over the area again. Once the putty is dry (about a week), it can be primed and painted with water-resistant paint to match the window frame.

Now YOU Have The Power
Once you have tackled a task as intensive as this one, you can honestly anoint yourself with the title Do-it-Yourselfer. Congratulations on your appointment; now go forth and repair!

Hammer Still need help with replacing window glass? Visit our Doors and Windows forum and talk to other DIYers who may just have the answers you need!