How to Replace Broken Window Glass

window and door mistakes edmonton albertaA broken window pane is … well ... a pain! But if it’s a single pane of glass in a traditional square or rectangular shape, it’s fairly easy to replace.

You will need:

Tape measure
Duct tape or masking tape
Glazing points
Putty aka Glazing Compound
Sandpaper and Wood sealer (optional but recommended)
Small brush
Putty knife
Screwdriver or chisel
Long nosed pliers
Heavy gloves and safety glasses


  • Wear heavy gloves and safety glasses when handling broken glass.
  • Apply duct tape or masking tape across all the cracks in the glass to keep the pieces together while you work.
  • Tape newspaper across the sash on the inside of the window to keep loose shards of glass from falling inside.
  • Measure the old glass from the outside of the window (side with the putty).

Steps for replacing the broken window (wood frame):

  • Still wearing your gloves and safety glasses, carefully remove the broken glass from the window. If necessary use a chisel to remove old putty and the pliers to remove the old glazier points.
  • Wrap the old glass in newspaper, a thick layer of paper towels, or other material so that you can transport it without injuring yourself. Bring it to your glass dealer along with the dimensions of the old window and ask them to match the glass, including any coatings, as closely as possible.
  • Remove any old glazing compound and glazier points still in the window frame, using your screwdriver or chisel to make sure you get all the old putty.
  • Brush away any debris.
  • Optional – lightly sand the wood and apply a coat of wood sealer
  • Put a thin rope of putty around the window opening to make a “bed” for the new window. You can press this in with a putty knife or your fingers.
  • Press the new pane of glass in place.
  • Remove any excess putty
  • Insert glazier points into the frame about every 4”-6” to hold the pane in place
  • Put more putty on top. Use your putty knife to smooth it at an angle.
  • Wait until the putty is dry, then paint.
Note that if the window frame is aluminum or vinyl, these use gaskets, spring clips or snap in molding to hold the window in place.

Replacing glass on a window with snap-in moldings is easy – gently pry up one end of each piece of molding with a screwdriver or putty knife, remove and replace the glass and snap the moldings back into place.  (Be prepared to make a run to your glass dealer in the event one of the moldings breaks during removal.)

If the window uses rubber gaskets or seals to secure the glass - you will need to remove part of the window sash to replace the glass. The part you need to remove depends on the type of seal or gasket being used.

For windows with rubber seals, you need to unscrew the two sash pieces, remove the inner one, replace the glass, and refasten them.  On windows that use a rubber gasket, you need to remove the bottom of the sash, remove the old glass, replace the gasket around the new glass, slide it into the sash and reattach the bottom sash piece.

This isn’t difficult, but it can be tricky. Consider calling a professional window repair service like Reflect Window and Door for help.

See also: Should you fix that broken window yourself or hire a pro?