How to Replace Window Panes
A cracked window pane can be a nuisance. It could also be an opportunity to upgrade your glass to energy-efficient or insulated windows to benefit from greater comfort, a higher the value of resales and lower utility bills.
You can do it yourself for less than what it would cost to hire an expert. You only need the appropriate tools and a few minutes of your time.
Glass
Replace your old single-paned windows with tempered insulation glass to improve energy efficiency, reduce noise, and maintain the original character of your old home. The process of replacing a window pane is relatively easy and can be completed by most homeowners who possess basic hand tools. In addition to a replacement pane, the following items are needed such as latex glazing putty; glazier’s points; pliers; and the use of a heat gun to warm the old putty, if needed. Wear safety glasses and gloves before you begin. Working with broken glass could cause serious injuries.
Remove any broken glass for window replacement (image source) pieces that remain. It is best to use pliers however, a flathead may be used equally. Make use of a wood chisel or putty knives, to take away any remaining old putty around the frame and the window sash. Be careful to not break the window sash. Work slowly and carefully. This should be done on a ladder, not on the ground. Also, have someone on the ground to hold it steady.
After you have removed all of the old putty, it is time to prepare the window frame to fit the new pane. Find the width and the height of the sash opening, subtracting 1/8 inch from each measurement (to allow for seasonal expansion and contraction). Bring these measurements to a hardware store or home center, and get a piece of stock glass cut to size. You can cut the glass yourself if you possess the appropriate tools.
After installing the new glass After installing the glass, apply a small amount of caulking around the edge. This will make the glass 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 sash and the frame, but they also shouldn’t be loose.
Before applying the putty, knead it thoroughly until it is soft and free of lumps. Then, roll it into pencil-size strips. Apply the first strip to the corner of the frame. Work from one corner to the next, making sure it is even and smooth.
Glazier’s Points
The glazier’s facets are tiny triangular pieces of steel which help to secure glass into a window frame without scratching or damaging the fragile surface. Understanding how to use these hidden little helpers is easy and could save you money on a professional installation or the cost of new glass.
After taking off the old putty, glazier points, and any other residue Clean the frame thoroughly with an utility knife. Lightly sand the frame in the rabbet grooves, if necessary, to smooth rough areas. If you sand wood protect it with painter’s tape to avoid accidental damage.
Write down the dimensions of the frame. Take these dimensions to a hardware store or a home center, and have the new pane cut slightly smaller than the frame’s opening. This will ensure that the pane fits perfectly and allows for expansion and contraction.
Place the new window in the frame and push it into place firmly by using your hands. Use the point of the chisel or the back of the putty blade to tap the glaziers’ points as illustrated in Figure 11. The glazier’s point should be aligned with the top edge of your pane and the raised shoulders should be just beneath 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. Let it dry and cure completely.
When the glazing compound is dry it’s time to put in the new window sash. First, coat the wood with a heavy coat of Linseed oil. This will prevent the new putty from drying out or cracking as it absorbs moisture. Apply this coat with a brush or the edge of your putty knife, then employ the chisel or back end from the putty knife to gently press the new sash and glazier’s points into the rabbet grooves. Repeat this process every 10 inches around the frame’s perimeter.
Putty
A hurled baseball or an unintentional rock, or a fallen branch can cause a window replacement panes pane to crack or break. Fortunately, the majority of windows can be easily replaced by simply putting a brand new piece of glass in its the right place. The glass is held in place by small clips made of metal called a glazier’s point, and putty, also called glazing compound. Remove the old pane and clean the area using a rag, a pull-type scraper or wood chisel. Wear protective glasses and gloves while working. You’ll require a heat gun if the window is glued into the frame.
If you are planning to replace the original sash, gently remove the molding pieces that secure the old pane. Then sand the sash to ensure it’s level and ready for a new caulk. After the sash has been reinstalled it is possible to apply a silicone caulk to the glass. This will ensure that it won’t get soiled or discolor over time.
Remove the glazing points from the rabbets and the grooves in the sash where the glass sits. If they’re difficult to cut, place a hand tool such as a heatgun over them for a few minutes to soften them. When using a heat tool, be careful to not damage the sash and its railings.
Once the old glazing points and putty are removed, make a bed for the new pane. Roll a piece of glazing compound between your hands, shaping it into a 1/2-inch thick. Press it into the rabbets where the glass will be put. The glass must 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 has a crack then you can seal it with a solvent-based glue or silicone caulk before pressing it into the sash. If not, you’ll have to apply putty over the crack to form an airtight seal and keep water out. After the putty has dried, clean the oily film off the glass with an abrasive and allow it to dry completely prior to painting. Paint before the putty has dried completely. It will not form a good seal and could leak or discolor with time.
Paint
You may be concerned about replacing a broken piece of glass. In reality, replacing a single piece of glass doesn’t need to be costly if you do it on your own. In fact even windows with double 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 that it is securely fixed to the frame. This job can be made relatively simple and fast using the appropriate tools and techniques.
When you’re ready to start, begin by removing the old window by removing the metal glazing points that are connected to it. They are basically tiny metal triangles that function as “nails” which hold the window in place within the frame of wood. They are buried under a bead of glazing putty that transforms into a solid formed wedge that holds the window firmly in place and hides the edges.
Once you have the old pane taken away clean the surrounding frame and wood. Scrape off any paint that has been used and sand the rabbet grooves in which the glazing points were. They should be sanded to bare wood, to allow you to paint them the same color as the rest of the frame. After sanding, apply a coat of flax oil to the wood’s surface to prolong its life.
Next, measure the dimensions of the window opening. It is necessary to measure the vertical and horizontal dimensions of the entire opening, as well as the thickness. To determine the exact size of the new pane subtract 1/8 inch from both measurements. This will also allow for expansion and contraction of the glass during seasonal change. Take these measurements to a 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.
