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.
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
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.
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.
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.