How to Replace Window Panes

A cracked window pane can be a source of frustration. It can also be a chance to upgrade your glass to energy-efficient or insulated windows and benefit from improved comfort, increased resale value and reduced utility bills.

You can do it yourself for only a fraction of the cost it would cost to employ an expert. You only need the right tools and a few minutes of your time.

Glass

If your single pane windows are old, deteriorating or broken, replacing them with newer insulated or tempered glass can improve energy efficiency and reduce noise while maintaining the original character of older homes. The replacement of the window pane is simple and can be done by anyone with basic hand tools. You will also need an extra window pane, glazier's tips pliers, and latex glaze putty. If needed you can make use of a heat gun to warm the old putty. Wear safety goggles and gloves prior to starting. Working with broken glass could result in serious injuries.

Take away any broken glass pieces that remain. This can be done with the help of pliers but a flathead screwdriver may be effective in a pinch. Make use of a wood chisel or putty knife to get rid of any old putty remaining around the frame and the window sash. Work slowly and carefully making sure not to break the existing window sash. It is a good idea to work on a sturdy ladder rather than on the ground and to have someone stand below the sash in order to help hold it steady.

After you have removed all the old putty, prepare the window frame to accommodate the new pane. Take measurements of the width and height of the opening for the sash and subtract 1/8 inch from each measurement (to allow for seasonal expansion and contraction). These measurements can be sent to a home center or hardware store to have cut a piece of glass that is in stock to the correct size. You can also cut the glass by yourself if you have the appropriate tools.

After installing the new pane After installing the new pane, apply a small amount of caulking around the edges to make it weatherproof. Install a glazier's point on both sides of the frame. This will secure the pane. The points shouldn't be so tight that they create friction between the frame and the sash however they should not be loose.

Before applying the putty to the surface, knead thoroughly until it is soft and free of lumps. Make it into pencil-sized strips. The first strip should be placed in the corner of the frame, working from one corner to the other to ensure it is even and smooth.

Glazier's Points

The glazier’s points are small triangular pieces of metal which help to secure the glass into the window frame without causing damage to the delicate surface. Understanding how to use these hidden tiny pieces of help is simple and could save you money on a professional installation or the cost of buying new glass.

After getting rid of the old putty glazier points as well as any remaining remnants Clean the frame thoroughly using an utility knife. 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 avoid accidental damage.

Take measurements of the empty frame and record precise measurements. These measurements can be taken to an hardware or home centers store, and the new frame will be cut a bit smaller. This will ensure that the pane fits comfortably and allows for expansion and contraction.

Insert the new pane into the frame and push firmly using your hands. Use the point of the chisel or the edge of the putty blade to tap in the glazier's points as illustrated in Figure 11. The glazier's point should be flush against the top edge of the pane and the raised shoulders should be just below the lip.

Apply a small amount of glazing compound over the edges of the glass that has been made and into the rabbet grooves to seal and protect them. Allow it to dry and cure completely.

Install the new window sash after the glazing compound has dried. First, saturate the wood with a thick coat of linseed oil. This will prevent the new putty from drying out or cracking due to the moisture it absorbs. Use a brush to apply this coat, or the tip of the blade. Then use the chisel on the back of the putty tool or the back of the handle to gently hammer the new sash or glazier's point into the rabbet grooves. Repeat this process at intervals of 10 inches all around the frame.

Putty

A baseball hit or a rock thrown in error, or a tree falling can cause a broken or cracked window pane. Luckily, most windows replacement glass can be easily replaced by simply putting a brand new piece of glass in its place. The glass is held in place by a small metal clip, referred to as the glazier's point, and putty. This compound is also known as glazing compound. Before installing a new pane, first remove the old one and clean the area with a rag and a pull-type paint scraper or a wood chisel. Wear protective glasses and gloves while doing this work. If the window is secured to the frame, you'll need to employ a heat gun in order to soften the adhesive before cutting it loose.

If you are planning to replace the original sash, remove any pieces of molding that hold the old pane in place. Then you can sand the sash down to ensure it's level and ready to be re-caulked. Once the sash is put back in place then, you can apply a silicone caulk to the glass. This will ensure that it won't be leaking or fade over time.

Take out the glazing points in the rabbets. These are the grooves in the sash, which is where the glass is. If they're difficult to work out, try placing the hand tool, such as a heat gun to soften them up first. If you're using a heated gun, be careful not to scratch the railings or sash by placing the tool too close.

Prepare the bed for your new pane after you have removed the old glaze points and putty. Roll a rope of glazing compound between your hands, forming it to be about 1/2-inch thick. Then, you can press it into the rabbets in which the glass will be. The glass must be positioned against the putty on both sides. If necessary, lightly tap your glass into the rabbet using your thumb.

If the new pane has a crack then you can seal it with a solvent-based glass glue or silicone caulk prior pressing it into the sash. In other cases, you'll need to apply putty over the crack to create an impervious seal to keep water out. When the putty dries, clean the oily film off the glass using the help of a rag. Allow it to completely dry before painting. Paint after the putty has dried completely. It will not make a strong seal and could leak or discolor with time.

Paint

If you've experienced a broken window pane, then you may be worried about the cost of replacing it. But the truth is that replacing one glass pane does not need to cost a fortune when you do it yourself. In fact even Replacements Windows with double glazed replacement windows panes can be replaced for only a fraction of the cost of an expert.

If you're working with large glass windows first, ensure that it is securely attached to the frame. With the right tools and techniques to make this task relatively easy and speedy.

If you're ready to begin taking off the old window by removing the glazing points of metal that are attached to it. These are essentially small metal triangles which function as "nails" that keep the window in place within the frame of wood. They are placed under a bead of glazing putty, which hardens into a solid, molded wedge which holds the window in place and conceals the edges.

After removal of the old pane clean the frame and the wood. Scrape away any old paint and sand down the rabbet grooves where the glazing points were. Sand them to bare wooden surfaces so you can paint the frames with the same color. After sanding, apply a coat of flax oil on the wood's surface to extend the life of the frame.

Next, measure the dimensions of the window opening. You'll need to determine the horizontal and vertical dimensions of the entire opening, as well as the thickness. 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 a piece 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.