How to Replace Window Panes

A damaged or cracked window can cause a lot of trouble. It can also be an opportunity to upgrade your glass to energy efficient or insulated windows, and reap benefits like greater comfort, a higher resale value and reduced utility costs.

You can do it yourself at 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 your old single-paned windows with tempered insulate glass to improve energy efficiency, reduce noise, and protect the historical integrity of your old home. The majority of homeowners with basic hand tools can repair windows with ease. You'll also require an additional window pane, glazier's tips, pliers, and latex glazing putty. If needed you may use a heatgun to warm the old putty. Before beginning, wear gloves and safety goggles as working with broken glass could cause injuries.

Begin by removing any remaining broken pieces of glass. This is best done using the help of pliers however, a flathead screwdriver may be used in a pinch. Then, use a wooden chisel, or putty knife, to remove the rest of the old putty from around the frame and the sash. Be careful not to damage the window sash. Be careful and slow. It is best to work using a sturdy ladder instead of the ground and have someone stand below the sash to help keep it steady.

Once you have removed all of the old putty, it is time to prepare the window frame to fit the new pane. To allow for seasonal expansion or contraction and contraction, subtract 1/8 inch from the measurements of the width and height. These measurements can be sent to a home center or hardware store to get a piece cut of glass stock to the proper size. Alternately, you can cut the glass yourself if have the appropriate tools.

After putting in the new pane after installing the new pane, put a tiny amount of caulking around the edge to make it weatherproof. Then, you can install a glazier's pointing on each side of the frame to secure the pane in place. The points should not be so tight that they create friction between the sash and the frame however they should not be too loose.

Before applying the putty on the surface, you must knead it thoroughly until it becomes soft and free of lumps. Roll it into pencil-sized strips. Apply the first strip to the frame's corner. Work from one corner to another to ensure it's even and smooth.

Glazier's Points

The glazier's points are small triangular pieces that allow glass to be secured into a window frame without scratching or damaging the fragile surface. It's easy to understand how to use this nefarious tool and you can save money on the expense of an expert installation.

After taking off the old putty, glazier points and any residue Clean the frame thoroughly using an utility knife. Lightly sand the wood in the rabbet grooves if needed to smooth rough areas. If you sand wood cover it with painter's tape to prevent accidental damage.

Write down the exact dimensions of the frame. Take these dimensions to a hardware store or a home center and have the new pane cut smaller than the frame's opening. This will ensure a secure fit and leave room for expansion and contraction.

Place the new pane in the frame and press it in place by using your hands. Use the chisel's point, or the back of the putty blade to tap in the glazier's points, as shown in Figure 11. The glazier's points should be aligned with the top edge of your pane and the raised shoulders should be just below the lip.

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

When the glazing compound is dry, you're ready to install the new window sash. First, coat the wood with a heavy coat of Linseed oil. This will prevent the new putty from drying out and cracking as it absorbs moisture. Apply the coat using a brush or the edge of your putty knife, then use the chisel or the back end of the putty knife to gently hammer the new sash and glazier's tips into the grooves of the rabbet. Repeat this procedure every 10 inches around the perimeter of the frame.

Putty

A hurled baseball, an errant rock or a fallen branch can cause a window to crack or break. The majority of windows can be replaced easily by simply putting in a fresh piece. The glass is held into the position with a tiny metal clip, referred to as the glazier's point, and putty. This compound is also referred to as glazing compound. Before you install a new pane, first take out the old one and wooden clean up the area with an abrasive and a pull-type paint scraper or the wood chisel. Wear protective glasses and gloves while doing this work. If the window is secured to the frame, you'll need to make use of a heat gun to soften the adhesive before taking it off.

If you are planning to replace the original sash, gently remove the molding pieces that hold the old pane in place. Then you can sand the sash down to ensure it's smooth and ready to be re-caulked. Once the sash is installed and sanded, apply a fresh silicone caulk to the glass to ensure that it won't leak or discolor in time.

Remove the glazing points from the rabbets. These are the grooves in the sash, where the glass is located. If they're hard to chisel, use the hand tool, such as a heatgun over them for a few minutes to soften them. If you're using a heating gun, make sure not to cause damage to the railings of the sash or the sash itself by holding the tool too closely.

After the old glazing points and putty have been removed, prepare a bed for the new pane. Roll a rope of glazing compound between your hands, and form it to be 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, lightly tap your glass into the rabbet using your thumb.

If the new pane is cracked, you can cover it with a solvent-based glue or silicone caulk prior to pressing it into the sash. In other cases, you'll need to putty over the crack to create a tight seal and keep water out. After the putty is dry and the film is oily, wipe it off the glass using the help of a rag. Allow it to dry completely prior to painting. If you paint before the putty is fully dry, it will not form an effective seal and could discolor or leak over time.

Paint

You may be concerned about replacing a damaged piece of glass. The truth is, replacing a single piece of glass doesn't have to be expensive even if you do it your own. In fact windows with double glazed replacement windows panes can be replaced at a fraction of the cost of a professional.

First, if you're working on a large-sized window, make sure it is securely fastened to the frame. This job can be done relatively easy and quick with the right tools and techniques.

When you are ready to begin, remove the old window pane. Pry out the metal glazing points that are attached to it. These are tiny triangles of metal which act as "nails" to hold the window within the frame. They are placed beneath a layer of glazing putty, which transforms into a solid moulded wedge which holds the window in place and conceals the window's points.

After you have removed the old pane taken away clean the surrounding frame and wood. Scrape away any paint and sand down the rabbet grooves where the glazing points used to be. Sand them to bare wooden surfaces so you can paint the frames with the same shade. After sanding the wood then apply a layer of flax oil. This will help extend its life.

Then, take measurements of the dimensions of the window's opening. You will need to take vertical and horizontal measurements of the entire opening as well as the thickness of the old pane. To determine the exact size of the new pane subtract 1/8 inch from both measurements. This will allow for seasonal changes in the glass. Bring these measurements to your local hardware or home improvement store, and they will have cut the glass 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.