Replacing Window Glass

Learn to replace glass safely with smooth glazing lines.


Replacing a broken single-glaze pane is messy and requires attention to detail, but with a bit of practice you can learn to install the glass safely and make smooth glazing lines. In most cases it is best to have a local hardware store or glass specialist cut the glass for you.

Unless the pane is very small, order double-thick glass; single-thick glass breaks easily. In a door, sidelight, or other high-traffic areas, order shatter-resistant glass.

Be sure to wear thick gloves, long clothing, and protective eyewear when handling shattered glass. Tiny, nearly invisible splinters can cause injury.

Traditional glazing putty (also called glazing compound) is applied with a putty knife. You can also buy glazing putty in a caulk tube, but applying with a knife creates a tighter bond and a smoother surface once you get the hang of it.

Often it is possible to replace double-glaze panes yourself; see the most common types of installation. In some cases you may need to take the sash into a hardware store or glass specialist for repairs.

Prestart Checklist

1 or 2 hours to replace most types of windowpanes

Tape measure, paint scraper, chisel, glazier's putty knife or standard putty knife, wire brush, heat gun, perhaps a glass cutter

Measuring carefully, applying glazing putty

Clear away shattered glass and place a drop cloth on the floor or ground below.

Glass pane to fit, glazing points, glazing compound (putty), linseed oil

Replacing glass in a wood frame: Step 1

Usually you can replace glass while the sash is still in the frame, but it is easier to remove the frame first and work on a table. While wearing protective clothing, wiggle and pull out the shards of glass. You may need to tap the glass with a hammer to create a new break line first.

Replacing glass in a wood frame: Step 2

Take care to remove all pieces of glass, putty, and metal glazing points. You may need to use a pull-type paint scraper or an old chisel. If you use a hammer, tap gently. The grooves where the new window will go must be completely smooth. A heat gun can help soften the old putty.

Replacing glass in a wood frame: Step 3

Wire-brush the frame and vacuum or wipe with a slightly damp rag. Apply a coat of linseed oil to the rabbet; this helps the putty stick securely.

Replacing glass in a wood frame: Step 4

Carefully measure the height and width of the opening in at least two places. Order a piece of glass 1/8 inch shorter in each direction. Test-fit the pane before proceeding.

Replacing glass in a wood frame: Step 5

Roll a ball of glazing compound into a thin rope. Press it into the corner of the rabbet. Then use a putty knife to press it firmly into place, making a thin bed of putty for the glass to rest against.

Replacing glass in a wood frame: Step 6

Gently press the glass into the putty bed, checking that it lies flat against the rabbet in all places. Every 6 inches or so, press a glazing point into the wood; push only gently against the glass as you go.

Replacing glass in a wood frame: Step 7

Roll a rope of putty about 3/4 inch thick. Aim for a fairly uniform diameter, but it need not be perfect.

Replacing glass in a wood frame: Step 8

Press the rope against the glass and the frame, using your thumb. Using a rag to periodically apply linseed oil to a glazier's knife or putty knife, press again using swiping motions every inch or two.

Replacing glass in a wood frame: Step 9

Working in the same direction and holding the knife at the correct angle so the putty will not be visible inside, press firmly and draw the knife along the line to smooth the putty.

Replacing glass in a wood frame: Step 10

If the resulting putty has a series of slight ridges, smooth them by lightly wiping with your finger, working in the opposite direction as in step 9.

Replacing glass in a vinyl frame: Step 1

Use a putty knife or small flat pry bar to remove the vinyl stop. Work carefully, to avoid cracking the stop. Remove the glass and order a new piece to fit.

Replacing glass in a vinyl frame: Step 2

Test to see that the new pane will fit. Scrape away the old sealing tape and clean the surface with paint thinner. Cut pieces of sealing tape to fit precisely and press them into place on the rabbet. Just before installing the glass, spread a bead of silicone sealant onto the rabbet.

Replacing glass in a vinyl frame: Step 3

Carefully set the pane in place -- you cannot adjust its position once it is set into the tape. Press the vinyl stop back into the frame to secure the glass.

Comments (1)
ashleyreedxx wrote:

One of the living room windows is broken, and I need to replace it. It has cardboard and duct tape on it right now, which isn't very safe. I don't know that I'll be able to replace it myself, but it's good to know how to do it!

3/25/2015 02:34:04 PM Report Abuse
Add your comment

You must be logged in to leave a comment. Register | Log In
Wish-list Projects

Making these dreams come true is simpler than you thought -- print these instructions to begin!