How to Replace Window Panes

A damaged window pane can be a nuisance. This can be an opportunity to upgrade your windows to energy efficient or insulated ones to enjoy benefits like increased comfort, increased resale values and reduced utility bills.

This is a project you could do yourself for a fraction of the cost of hiring an expert. You only need the proper tools and a few minutes of your time.

Glass

If your single pane windows are old broken, deteriorating or damaged replacing them with modern glass that is tempered or insulated will increase energy efficiency and reduce noise while maintaining the original character of older homes. A majority of homeowners with hand tools can replace a window pane. In addition to a new pane, the following components are needed: latex glazing putty; Glazier's points; pliers and the use of a heat gun to warm the old putty if required. Before starting, wear gloves and safety goggles as working with broken glass may cause injuries.

Begin by removing any broken pieces of glass. It is best to use pliers for this however a flathead could be used as well. Make use of a wood chisel or putty knives, to take away any old putty remaining around the frame and the window sash. Work slowly and carefully making sure not to damage the old window sash. This can be done best on an elevated ladder, not on the ground. Also, have someone below the sash ensure it is held steady.

Make sure the window frame is ready to accept the new pane once you have removed the old putty. Take measurements of 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 the nearest hardware store or home center and find a piece glass cut to size. Alternatively, you can cut the glass yourself if you have the tools you need.

After installing the new glass, apply caulking around the edge. This will make the glass weatherproof. Then, place a glazier's tip on each side of the frame to secure the pane in the right place. The points should not be tight enough to cause friction between the frame and sash however they should not be loose.

Before applying the putty work it in a gentle manner until it is soft and free of lumps. Then you can roll it into pencil-sized strips. The first strip should be glued to the frame's corner. Work from corner to corner and ensure that it is even and smooth.

Glazier's Points

The glazier's points are the small triangular pieces that allow glass to be secured into a window frame without damaging or scratching the delicate surface. Understanding how to use these tiny helpers is simple and could save you money on professional installation or the cost of new glass.

After removing the old putty, nearest glazier points, and any other leftovers clean the frame thoroughly using a utility knife. If needed, lightly sand the wood along the rabbet grooves to smooth rough areas. If you do sand the wood, make sure to protect it by using painter's tape to prevent accidental damage.

Measure the empty frame's dimensions and write down accurate measurements. Bring these measurements to an hardware store or home center and request that the new pane made slightly smaller than the frame's opening. This will ensure a snug fit and will allow room for expansion and contraction.

Place the new pane in the frame and push it in with your hands. Use the point of the chisel or the back of the putty knife to tap in the glazier's points as shown in Figure 11. When you're done taping, they should be flush with the top edge of the pane, and the shoulders of the points should be below the lip of the rabbet groove.

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

Install the new window sash after the glazing compound has dried. First, coat the wood with a heavy coat of linseed oil. This will prevent the newly-created putty drying out or cracking when it absorbs moisture. Apply the coating using a brush this coat, or the tip of the putty blade. Then use the chisel that is on the back of the tool or the back of the handle to gently hammer the new sash or glazier's point into rabbet grooves. Repeat this process in intervals of 10 inches around the frame.

Putty

A baseball thrown at you or a rock that is errant or falling branch could cause a window to crack or break. Most windows can be replaced easily by simply putting in a fresh piece. The glass is held in place with a small metal clip called a glazier's point, and putty, often called glazing compound. Before you install a new pane, first remove the old one and clean the area using the help of a rag, the pull-type paint scraper or an abrasive wood chisel. Wear gloves and safety glasses when you work. If the window is glued 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 install the original sash, take off the mold that holds the old pane. Then you can sand the sash down to make sure it's flat and ready for new caulk. Once the replacement sash windows is re-installed, apply a new caulk made of silicone around the glass to ensure it will not leak or change color over time.

Take the glazing points out of the rabbets, or the grooves in the sash, where the glass is. If they are hard to chisel, hold a hand tool like a heat gun over them for a few minutes to soften them. If you're using a heated gun, be cautious not to cause damage to the railings of the sash or the sash itself by placing the tool too closely.

Create a bed for your new pane by removing the old glaze and putty. Roll a piece of glazing compound between your hands, and form it to be around 1/2-inch thick. Place it into the rabbets, where the glass will be put. It is essential that the glass sits on the putty on both sides If you have to, lightly tap the glass into the rabbet using your thumb.

If the new pane is cracked, you can apply the silicone caulk or glass glue made from solvents to seal the crack prior to pressing it in the sash. If the crack isn't sealed, you will require putty to keep the water out. After the putty has dried remove the oily film off of the glass and allow it to dry completely before painting. Paint after the putty has completely dried. It will not create a solid seal and may discolor or leak over time.

Paint

You may be concerned about replacing a broken piece of glass. However, replacing a single glass pane doesn't need to cost a fortune if you do it yourself. Even a replacement double glazed windows-paned window could be replaced for a fraction of the price it would cost for nearest a professional.

If you are working on a large window, make sure that it is securely attached to the frame. This task is relatively easy and fast with the appropriate tools and techniques.

When you are ready to start taking down the old window pane. Pry out the metal glazing points that are attached to it. These are tiny metal triangles that function as "nails", holding the window in the frame. They are placed under a glaze putty or bead which hardens into solid wedge which holds the wood frame securely in place and conceals the edges.

Once you have the old pane taken away clean the surrounding frame and wood. Scrape away any old paint and sand down the rabbet grooves where the glazing points were. Sand them down to clean wooden surfaces, allowing you to paint the frames the same color. After sanding the wood, apply a layer of flax oil. This will help prolong the life of the frame.

Next, measure the size of the window's opening. It is necessary to measure the vertical and horizontal dimensions of the entire opening as well as the thickness. To get the exact size of the new pane subtract 1/8 inch from both measurements. This will allow for seasonal changes in the glass. Take these dimensions to the hardware or home improvement store and 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.