How to Repair a Single-Pane Window That Has a Broken Pane of Glass


The glass of a window may easily be shattered by an inaccurate baseball, a rock launched by the blade of a lawnmower, or even a bird flying in the wrong direction. The occasionally shattered pane of glass is just a part and parcel of being a homeowner. If the window uses shielded “thermo-pane” glass, which consists of two glass panels surrounding an empty space, fixing it requires a visit from a glazier or an attends from a window organization to rebuild the entire sash. If the window does not use this type of glass, repairing it does not require either of these visits. Whether you shine a light through the window from inside when it is dark outside, you will be able to see if the window is made up of more than one pane. In situations when the window is composed of more than one glass, the light reflections will be repeated. For instance, while looking out of double-paned windows, you’ll see two reflections, one right next to the other.

If, on the other hand, you have older windows with wood frames and single pane glass, it should not be too difficult for you to repair any broken glass yourself. You will only need a few simple tools and components, including some that you may already have in your possession. Other supplies may be obtained without much difficulty at home improvement shops or hardware stores.

Always keep in mind that dealing with glass presents some degree of inherent risk. Always be sure to protect your eyes with safety glasses and your hands with thick gloves.

The Components That Make Up a Single-Pane Window

Before beginning this project, it is essential to get an understanding of the method by which a window pane with a single pane is attached to the wood frame. The structure of a single-pane window will be recognizable to you if you have ever dealt with glass picture frames that have bending metal supports at the back. The single-pane window has glazing points that are metal triangles and they are used in place of the metal stays. These very little metal triangles serve the function of “nails” in holding the glass in place inside the wooden frame.

After that, the glazing points are hidden by a bead of a glazing compound that is shaped into a wedge shape and allowed to set. This wedge both seals the glass and conceals the glazing points. This technique is nearly undetectable after it has been painted to match the window.

Note that some kinds of windows will have a wood or vinyl bead molding that will be nailed into place at regular intervals to keep them in their proper position. In this scenario, the molding may be prised away, and either it or a new one can be installed in its place. Before nailing on the new bead, you should first run a thin bead of caulking all the way around the edges of the new glass. When driving the nails into the molding, use a hammer to get them started and then switch to a nail set to complete the job. This will prevent the hammerhead from colliding with the new glass and breaking it. If you have access to a power brad nailer, it would be your best option.

The procedure of replacing a pane of glass that has been damaged involves first removing the hardened glazing and the glazing points, then removing the shards of glass, and then installing a brand new pane of glass together with brand new glazing points and glazing.

What You Will Require

  • Equipment / Tools
  • Gloves for working with leather
  • Protection for the eyes
  • Putty knife
  • a chisel for wood or a razor scraper
  • Paintbrush
  • Tape measure
  • Pencil (optional)
  • Straightedge made of metal (optional)
  • Glass cutter (optional)
  • Rubber mallet
  • Materials
  • Fine-grit sandpaper
  • Linseed oil or a wood sealant that is transparent
  • The glass that was chopped to size as a replacement
  • Glazing points
  • Glazing compound
  • Exterior-grade paint



Watch this video slao.

1. Take the shattered glass out, then wipe off the frame.

To remove the glazed compound that has become rigid around the glass, use a putty knife to pry it away. Because it is often fairly dry and brittle, it should break off into huge pieces when you try to remove it. Remove any particles of the compound that are affixed to the wood by scraping them off.

To pry away the old glazing points, you may make use of pliers, a putty knife, or a thin screwdriver with a flat head. These minute fasteners have sharp points that are inserted into the wood, and they are used to secure the glass inside the recess of the frame. Clear up all of the shattered glass while protecting your eyes and handling it with strong gloves.

When you have finished removing the glazing compound and glazing points from the frame, use a razor scraper or chisel to scrape down the L-shaped channel that is surrounding the frame. Take care not to gouge the wood with your tool. Sand the wood to a smooth finish using sandpaper with a fine grit, and then use a paintbrush to apply linseed oil or a clear wood sealant to any exposed wood areas. Allow the sealer to dry to its final state.

How to Repair a Single-Pane Window That Has a Broken Pane of Glass

2. Determine the dimensions of the frame, then purchase the glass

Take measurements of the window opening’s width and height, being careful to measure all the way to the outer margins of the L-channels. When determining the size of the glass, deduct 1/8 of an inch from each measurement. It is simpler to install the pane if it is somewhat undersized, and this also leaves space for the pane to expand and contract with the changing seasons.

Take these dimensions to a home improvement shop or hardware store and ask them to cut a piece of glass to these specifications for you.

How to Repair a Single-Pane Window That Has a Broken Pane of Glass

3. Another method is to cut the glass yourself.

You also have the option of cutting a piece of glass yourself if you have access to a big sheet of stock glass and choose to do so.

Put the glass down on a clear, level surface of the work area. Use a marker that won’t wipe off to make the markings for the cutting line. After making the mark, position a metal straightedge on it, and then use a glass cutter to score the cutting line into the glass. A tiny metal wheel is often found on a glass cutter, and this wheel is used to score the glass. Move the cutter along the straightedge while maintaining a steady downward pressure on the wheel. Only one cut should be made using the cutter. Before moving on to the following step, check that you are wearing protective eyewear and gloves.

Move the glass around the edge of your work surface until the scribed line on the glass is in the same position as the border of the surface. One hand should be used to hold the main section of the glass, while the other should be used to press down firmly on the waste portion of the glass in order to cause it to break along the scored line. When handling the cut glass, use extreme caution since the edges will be quite jagged.

Read related articles here also: General Tech/Our Blog

4. Put the Glass in Place.

The glazing compound may be rolled out into long, extremely thin ropes with a diameter of approximately 1/8 of an inch. Place the ropes in the L-channels that are located around the perimeter of the window frame. This is where the glass will eventually sit. The edge of a putty knife should be used to apply mild pressure all the way around the perimeter of the glass in order to gently compress the glazing compound and bed the glass in place.

Put the tip of the putty knife to the glass and press two glazing points into the bottom of the frame so that they are pressed against the glass and into the wood. If you need more power, you may push the points in by tapping the handle of the putty knife with a rubber mallet in light and steady motion. Install two extra glazier points on either side of the window pane, bringing the total number of glazing points to eight for each pane.

Putty knife work is required to remove any glazing compound that has leaked out of the glass on the reverse side of the window.

How to Repair a Single-Pane Window That Has a Broken Pane of Glass

5. Put Glass in the Window.

Continue to roll more glazing compounds between your palms to produce ropes. The ropes should be approximately an inch and a half thick. Place these ropes of compound over the glazing points in the gap that is formed like an L and is located where the glass meets the window frame. Put some pressure on the compound by pressing it against the glass and the wood with your finger.

Form a flat, angled wedge at the junction between the glass and the window frame by running the blade of a putty knife along with the bead of the glazing compound while holding the putty knife at a 45-degree angle. You may achieve this by holding a putty knife at an angle. If you find that there are spaces in the compound, add a little bit more, and then run the putty knife over the joint one more time to smooth it out.

When you have the glazing compound molded into a perfect wedge and the seal is complete, use the tip of the putty knife to gently remove any little particles of the glazing compound that may be on the glass. Take care not to touch the final bead of glazing compound, and keep your hands away from it.

The process of glazing windows might be difficult, but with little training and experience, it can be accomplished. The end result should be a piece of glass that is securely fastened in place by a perfect wedge of the compound that wraps around all four edges. Because the compound will maintain its malleability for a considerable amount of time, if you make a mistake while working with it, you can easily remove the glazing compound and begin the process again.


Warming up glazing compounds makes it much simpler to shape into desired shapes. Before commencing, if the weather is chilly you may briefly warm the can of glazing compound by placing it over a heater. The compound will warm up as a result of your manual manipulation, which will also make it simpler to deal with.

How to Repair a Single-Pane Window That Has a Broken Pane of Glass

6. Wait for the Glazing to Dry, and Then Start Painting

Wait for the glazing compound to dry and harden in accordance with the time recommendation provided by the manufacturer. This might take anywhere from five to seven days.

Paint the glazing and any exposed wood with paint designed for use outside after it has dried and become completely firm. Paint is often overlapping onto the glass by the smallest of margins—perhaps 1/16 of an inch—when it is being applied by professionals. This is done to achieve the finest possible weather seal.

Once the paint has reached its final dry state, clean the glass.

How to Repair a Single-Pane Window That Has a Broken Pane of Glass

Leave a Comment

Your email address will not be published. Required fields are marked *