How to Replace Window Panes

A damaged or cracked window can be a source of frustration. It can also be an opportunity to upgrade your glass to energy-efficient or insulated windows and benefit from improved comfort, increased the value of resales and lower utility costs.

You can do it yourself for a a fraction of what it would cost to hire an expert. It requires the right tools and only an hour or two of your time.

Glass

Replace window pane your single-paned replacement windows using tempered or insulate glass to improve energy efficiency, cut down on noise, and preserve the historical integrity of your old home. The majority of homeowners with basic hand tools can replace a window pane. You will also require an extra window pane, glazier's suggestions, pliers, and latex glazing putty. If needed, you can make use of a heat gun to warm the old putty. Wear safety goggles and gloves prior to beginning. Working with broken glass can cause serious injuries.

Begin by removing any remaining broken pieces of glass. This can be done with pliers, though using a flathead screwdriver can also be effective in a pinch. Utilize a wood chisel or putty knife to get rid of any old putty that remains around the frame and window sash. Work slowly and carefully and be careful not to damage the old window sash. It is a good idea to work using a sturdy ladder rather than the ground and to have someone standing below the sash to help hold it in place.

Prepare the window frame to accommodate the new pane once you have removed the old putty. Measure the width and height of the sash opening and subtract 1/8 inch from each measurement (to allow for seasonal expansion and contraction). Take these measurements to an hardware store or home center, and find a piece glass cut to size. Alternately, you can cut the glass yourself if you have the right tools.

After putting in the new pane after installing the new pane, put a tiny amount of caulking along the edge to seal it against weather. Then, place a glazier's tip on each side of the frame to secure the pane into the right place. The points shouldn't be too tight that they cause friction between the sash and the frame but they shouldn't be too loose.

Before putting the putty on, make sure to knead it until it is soft and free of lumps. Make it into pencil-sized strips. Place the first strip to the corner of the frame, moving from one corner to the next so that it is even and smooth.

Glazier's Points

The glazier's points are tiny triangular pieces of steel that allow glass to be secured into a window frame without damaging or scratching the delicate surface. It's easy to learn how to use this hidden tool and you can save money on the cost of a professional installation.

Once the old putty and glazier's points are removed Clean the frame thoroughly with a utility knife to remove any remaining traces. Lightly sand the frame in the rabbet grooves if needed to smooth rough areas. If you sand wood protect it with painter’s tape to prevent accidental damage.

Take the dimensions of the frame and write down accurate measurements. These measurements can be brought to an hardware or home centers store, and the new pane will be cut a bit smaller. This will ensure a tight fit and will allow room for expansion and contraction.

Place the new pane in the frame and push it into the frame using your hand. Then, you can use the point of your chisel, or the back of the putty knife to tap in the glazier's points as illustrated in Figure 11. The glazier's points should be aligned with the top edge of your pane and the shoulders should be just below that lip.

Apply a thin layer of glazing compound on the rabbet grooves as well as the edges of new glass. This will seal and protect the edges. Allow it to dry completely and cure.

After the glazing compound dries and the glazing compound is dry, you can install the new window sash. The first step is to coat the wood with an even layer of linseed. This will prevent the newly-created putty drying out or cracking when it absorbs moisture. Apply this coat using a brush or the tip of your putty knife, then employ the chisel or back end of the putty knife to gently hammer in the new sash and glazier's points into the rabbet grooves. Repeat this procedure every 10 inches around the frame's perimeter.

Putty

A baseball that is thrown or an unintentional rock, or falling branch could cause a window pane to crack or break. Luckily, most windows replacement can be easily replaced by simply placing a new piece of glass in its the proper place. The glass is held into place by a small metal clip, called a glazier's point and putty. This compound is also known as glazing compound. Remove the old pane and clean the area using the rag, a scraper that is a pull type or a wood chisel. Wear safety glasses and gloves when working. You'll need a heating gun if the window is glued to the frame.

If you are planning to replace the original sash, gently remove the molding pieces that are used to secure the old pane. Then sand the sash to ensure it's smooth and ready for a new caulk. Once the sash is installed then, you can apply a silicone caulk on the glass. This will ensure that it won't leak over time or discolor.

Take the glazing points out of the rabbets and the grooves in the sash where the glass is. If they're difficult to chisel, use an instrument such as a heating gun over them to soften first. If you're using a heating gun, be careful not to scratch the sash or its railings by holding the tool too closely.

After the old points of glazing and putty are removed, prepare a bed for the new pane. Roll a rope with glazing compound between your fingers, and then make it about 1/2 inch thick. Press it into the rabbets, where the glass will be placed. The glass should rest against the putty on both sides. If necessary you want to tap your glass lightly into the rabbet using your thumb.

If the new pane is cracked then you can seal it with a solvent-based glass glue or silicone caulk prior to pressing it into the sash. If not, you'll have to putty over the crack to create a tight seal and keep water out. After the putty has dried, clean the oily film off the glass with a rag and allow it to dry completely prior to painting. If you paint before the putty has completely dry, it won't create an effective seal and could discolor or leak in time.

Paint

You might be worried about replacing a damaged piece of glass. But the truth is that replacing one glass pane does not need to cost a fortune If you can do it yourself. Even a double-paned window can be replaced at a fraction of the cost it would cost an expert.

If you are working with a large glass window first, ensure that it is securely attached to the frame. With the right tools and techniques, you can accomplish this task fairly easily and quick.

When you are ready to start, remove the old window pane. Pry out the metal glazing points attached to it. These are small metal triangles which act as "nails" to hold the window within the frame. They are buried beneath a bead or replace Window pane glazing putty which hardens into a solid wedge that holds the wood frame firmly in position and hides the points.

Once you have the old pane taken away, clean up the surrounding frame and wood. Scrape off any paint and sand down the rabbet grooves, where the glazing points were. Sand them to bare wood surfaces, so that you can paint the frames with the same color. After sanding the wood, apply a layer of flax oil. This will help extend its life.

Then, you need to measure the width of the window's opening. It is necessary to take vertical and horizontal measurements of the entire opening and also the thickness of the old pane. Subtract 1/8 inch from each measurement to ensure you get a precise size for the new pane. This will allow for seasonal changes in the glass. Take these dimensions to the hardware or home improvement store and have the glass cut for you.

Now, it's time to bed the new window pane. To do this, place the pane inside the frame and move it around until a 1/16 inch of putty remains between the edge of the glass and the sash on all four sides. Use a putty knife to smear the putty evenly, making sure that there isn't an excessive amount of excess putty in the corners and along the edges. When the putty dries, it can be painted with the same color as the frame to prevent water and air from leaking into the frame and causing fogging.