How to Replace Window Panes

A damaged or cracked window can cause a lot of trouble. 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 a fraction of what it would cost to hire an expert. It requires the right tools and an hour or two 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 can improve energy efficiency and reduce noise while maintaining the historical integrity of older homes. The majority of homeowners with basic hand tools can repair windows with ease. In addition to a new pane, the following tools are required: latex glazing putty; pliers, glazier's points and a heat gun for warming the old putty if required. Before starting, put on gloves and safety goggles as working with broken glass could cause injuries.

Remove any broken glass pieces that remain. It is best to use pliers for this, but a flathead can work equally. Make use of a wood chisel or putty knives, to take away any old putty that remains around the frame and window sash. Take your time and work slowly making sure not to break the existing window sash. This can be done best on an elevated ladder, not on the ground. Also, you should have someone on the ground to ensure it is held steady.

Prepare the window frame to receive the new pane after you have removed the old putty. Take measurements of the width and height of the sash opening, subtracting 1/8 inch from each measurement (to allow for seasonal expansion and contraction). Take these measurements to a hardware store or home center and get a piece of stock glass cut to 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, put a tiny amount of caulking around the edges to ensure it is weatherproof. Install a glazier's point on both sides of the frame. This will ensure the pane. The points shouldn't be so tight that they cause friction between the frame and sash However, they should not be loose.

Before applying the putty to the surface, knead thoroughly until it is soft and free of lumps. Cut it into pencil-sized pieces. Apply the first strip to the corner of the frame. Work from one corner to the next and ensure that it is even and smooth.

Glazier's Points

The glazier's points are the tiny triangular pieces of steel that help secure glass into a window frame without scratching or installing damaging the delicate surface. It's easy to learn how to use this secret tool, and you'll save money on the expense of an installation by a professional.

Once the old putty and the glazier's point are gone, thoroughly clean the frame using a utility knife to get rid of any remaining traces. If necessary you can lightly sand the wood along grooves of the rabbets to smooth out rough areas. If you sand wood protect it with painter’s tape to prevent accidental damage.

Take the dimensions of the frame and note down precise measurements. These measurements can be taken to an hardware or home centers store, and the new pane will be cut slightly smaller. This will ensure a snug fit and will allow room for expansion and contraction.

Place the new pane into the frame and push it into the frame with your hand. Then, you can use the point of your chisel, or the back of the putty knife to make a tap on the glazier's points, as illustrated in Figure 11. After you're done, the points should be level with the top edge of the pane. the shoulders of the points should be below the lip of the rabbet groove.

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

Install the new window sash once the glazing compound has dried. First, coat the wood with a thick layer of linseed. This will stop the new putty from drying out or cracking when it absorbs moisture. Apply the coat using a brush or the edge of your putty knife, and then use the chisel or the back end of the knife to gently press the new sash and glazier's point into the rabbet grooves. Repeat this process in intervals of 10 inches around the frame.

Putty

A baseball that is thrown, an errant rock or falling branch could cause a window pane to break or crack. The majority of windows can be replaced by simply putting in a fresh piece. The glass is held in position by a small metal clip, called a 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 clean up the area using an abrasive and an abrasive scraper that is a pull type or the wood chisel. Wear protective glasses and gloves while you do this work. You'll require a heat gun in the event that the window is glued to the frame.

If you're planning to install your original sash, you must remove the molding that supports the old pane. Then, sand the sash to ensure it's smooth and ready for new caulk. Once the sash is re-installed then, apply a new silicone caulk around the glass to ensure that it won't leak or discolor in time.

Remove the glazing points from the rabbets and the grooves in the sash that the glass sits. If they are hard to chisel, hold an instrument such as a heatgun over them for a few minutes to soften them. When using a heated tool, be careful to not scratch the sash's railings and sash.

Once the old glazing points and putty have been removed make a bed for the new pane. Roll a piece of glazing compound between your hands, forming 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 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 pressing it into the sash. If the crack is not sealed, you will need to apply putty to keep water from getting in. After the putty has dried then clean the oily film off the glass with an abrasive and allow it to completely dry before painting. If you paint before the putty is fully dry, it will not form a strong seal and may discolor or leak over time.

Paint

You may be concerned about replacing a damaged piece of glass. However, replacing one glass pane does not need to cost a fortune if you do it yourself. In fact, even a double glazing replacement window-pane window can be replaced for only a fraction of the cost of an expert.

If you're working with a large glass window, first make sure it is securely attached to the frame. This job can be made relatively simple and fast with the appropriate tools and techniques.

When you are ready to begin taking down the old window pane. Pry out the metal glazing points that are attached to it. These are tiny metal triangles that act as "nails" that hold the window in place. They are buried beneath a layer of glazing putty, which transforms into a solid moulded wedge which holds the window in place and hides the edges.

After taking off the old pane clean the frame and the wood. Scrape off any old paint and sand down the rabbet grooves that the glazing points were. They should be sanded to bare wood, to allow you to paint them the same shade as the rest of the frame. After the sanding process, apply a coat of flax oil on the bare wood to help extend its lifespan.

Then, take measurements of the dimensions of the window's opening. You will need to take vertical and horizontal measurements of the entire opening, and also 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. Take these measurements to your local hardware or home improvement store and ask them to cut you 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.