The charm of an old-fashioned wooden window can add a lot of warmth to a home. However, as with a lot of things in older homes, wooden windows can present some significant challenges for homeowners. One of the trickiest repairs to make on an old window is replacing broken glass panes. In some cases, buying a new window may make the most sense depending on the age and condition of the old window. However, it is definitely possible to replace broken glass yourself; it takes patience and using the right tools and materials to be successful, but the end result is often worth the effort. Below is how you do it:
Tools and materials you will need
- Replacement glass pane – replacement glass panes are available, cut to size, from a local glass repair or supply store.
- Window glazing putty – a quality, brand-name, linseed oil putty works well and can be purchased from home improvement and hardware stores.
- Putty knife – use a plastic blade knife for working the putty into the edges.
- Glazing points – these small, metal pins push into the sash and hold the glass pane in place; they are also available at home improvement and hardware stores.
- Measuring tape
- Flathead screwdriver
- Thin chisel
- Adjustable pliers
- Needle-nose pliers
- Compressed air
- Masking tape
- Cut-resistant gloves
- Safety glasses
How to replace the glass
1. Remove the broken shards of glass – wearing your eye protection and cut-resistant gloves, use pliers to pull out pieces of broken glass from the sash grooves. Use your screwdriver to pry loose stubborn pieces, but be careful not to crack or gouge the wood or shatter neighboring panes of glass.
2. Clean out the grooves – once the glass shards are removed, scrape out the inside of the groove with a thin chisel. Pull out any old glazing points with your needle-nose pliers so the interior surface is smooth and clean. Use a blast or two of compressed air to remove fine particles of glass, but be sure that you continue to wear eye protection to prevent getting small pieces of glass in your eyes.
3. Measure from groove-to-groove – you will need to take precise measurements of the distance between grooves on both the vertical and horizontal dimension. Subtract one-eighth of an inch from both dimensions, and provide these reduced dimensions to the glass supplier for use in cutting the new pane.
4. Apply putty to the sash – after your new pane is cut, lay the sash flat on a well-lit workbench or other flat, firm surface. Make sure that the sash is lying so the rabbet, the thin strip of wood that supports the glass, is on the backside. Take a small ball of glazing putty from the can and work it with your bare fingers until it is evenly mixed with the oil. Roll the putty in your hands to form a long "rope" about one-sixteenth of an inch in diameter. Push the putty rope into the groove all the way around the interior of the sash; use more putty if your rope isn't long enough.
5. Seat the glass pane – once you have placed your putty rope, lay the glass pane on top of the rope and gently push it down so it sits firmly in position. Center the glass pane so there is a one-sixteenth of an inch expansion gap around all edges of the glass.
6. Insert the glazing points – push glazing points into the grooves so they pin the glass pane down. Use a pair of needle-nose pliers to firmly push the points into place, but be careful not to crack the glass or break the sash. Insert points about every four to six inches, but be sure that each edge of the glass is held in place by at least two points.
7. Apply the top putty rope – again, form a small ball of putty and roll out a rope about one-eighth of an inch in diameter with your hands. Apply the rope into the groove on the top side of the glass so it covers the points and extends around all four edges of the sash. Use the putty knife to push the putty into a concave shape so it is firmly attached to the glass and sash.
8. Paint the putty – after the putty has dried on both sides of the glass, it is ready to be painted. Apply one or two coats of a latex paint on top of the putty, and allow the paint to overlap by a small margin on the glass. The paint will help seal any small gaps between the putty and glass to prevent moisture intrusion. A strip of masking tape on the glass about one-sixteenth of an inch from the edge of the putty may help you paint a neater edge, but don't forget to remove the masking tape after the paint has dried.
If you need assistance with your window repairs, contact a local window installation company, or click here for more information.