How to Replace Window Panes

A cracked window pane can cause a lot of trouble. This could be an opportunity to upgrade to energy-efficient windows or insulated ones and enjoy advantages like improved comfort, higher resale value and reduced utility bills.

This is a project you could tackle yourself at a fraction of the cost of hiring an expert. It requires the right equipment and an hour or two of your time.

Glass

If your single pane windows are old, deteriorating or broken replacing them with more modern glass that is tempered or insulated will increase energy efficiency and decrease noise while preserving the original character of older homes. The replacement of a window pane is relatively simple and can be done by most homeowners who possess basic hand tools. You will also need a replacement window pane, glazier's tips, pliers, and latex glaze putty. If needed you can use a heatgun to warm the old putty. Wear safety goggles and gloves prior to beginning. Working with broken glass could result in serious injuries.

Take away any broken glass pieces that remain. It is best to use pliers for this, but a flathead can work equally. Use a wood chisel, or putty knives, to take away any remaining old putty around the frame and window replacement sash. Take your time and work slowly, taking care 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 below the sash ensure it is held steady.

Once you've removed all the old putty, it is time to prepare the window frame to fit the new pane. 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). Bring these measurements to the nearest hardware store or home center and have a piece of stock glass cut to size. You can cut the glass yourself if you possess the right tools.

After putting in the new glass Apply caulking to 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 should not be so tight as to cause friction between the frame and sash, but they also shouldn't be too loose.

Before putting the putty on, knead it thoroughly until it's 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 and ensure that it is even and smooth.

Glazier's Points

The glazier's points are tiny triangular pieces of steel that help secure glass into a window frame without scratching or damaging the fragile surface. It's easy to understand how to use this hidden tool and you can save money on the cost of an expert installation.

Once the old putty and the glazier's points have been removed Clean the frame thoroughly using a utility knife to eliminate any remaining residue. Lightly sand the wood in the rabbet grooves, if necessary, to smooth rough areas. If you do sand your wood, make sure to protect it with painter's tack to avoid accidental damage.

Write down the exact dimensions of the frame. Take these measurements to an hardware store or home center and request that the new pane cut slightly smaller than the frame's opening. This will ensure a secure fit, and allow for expansion and contraction.

Place the new pane into the frame and push it into the frame by using your hands. Utilize the point of the chisel, or the back of the putty blade to tap in the glazier's points, as illustrated in Figure 11. The glazier's points should be flush against the top edge of your pane, and the shoulders raised should be just beneath that lip.

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

Install the new window sash once the glazing compound has dried. The first step is to coat the wood with an even layer of linseed. This will keep the new putty from sucking up the moisture and replace window pane deteriorating and cracking over time. Apply this coat with a brush or the tip of your knife, then use the chisel or the back end of the putty knife to gently hammer in the new sash and glazier's points into the rabbet grooves. Repeat this process at intervals of 10 inches all around the frame.

Putty

A baseball thrown, a rock thrown in error, or a tree falling can cause a broken or cracked window pane. Fortunately, windows can be replaced by simply placing a new piece of glass in its the proper place. The glass is held into position by a small metal clip, also known as a glazier's point and putty. This compound is also referred to as glazing compound. Before you install a new pane, first remove the old one and clean up the area using an abrasive and a pull-type paint scraper or a wood chisel. Wear protective glasses and gloves while you do this work. You'll need a heat gun in the event that the window is glued into the frame.

If you are planning to replace Window Pane the original sash, gently remove any molding pieces that hold the old pane in place. Then sand the sash to make sure it's flat and ready to be re-caulked. After the sash has been re-installed, apply a new caulk made of silicone around the glass to ensure that it won't leak or discolor over time.

Remove the glazing points from the rabbets. These are the grooves in the sash, which is where the glass is located. If they're difficult to cut out, try placing an instrument like a heat gun over them to soften them up first. If you're using a heating gun, be careful not to cause damage to the sash or its railings by placing the tool too close.

After the old glaze points and putty have been removed prepare a bed for the new pane. Roll a rope of glazing compound between your fingers, and make it 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 you need to, lightly tap your glass into the rabbet with your thumb.

If the new pane has cracked, you can apply a silicone caulk or glass glue based on solvents to seal the crack prior to pressing it into the sash. Otherwise, you'll need to apply putty on the crack to create a tight seal and keep water out. Once the putty is dry remove the oily film off the glass and allow it to dry completely before painting. Paint after the putty is completely dry. It will not create a solid seal and may be leaking or discoloring over time.

Paint

You may be concerned about replacing a broken piece of glass. The truth is, replacing a single pane glass doesn't need to be expensive if you do it on your own. In fact even windows with double glazing replacement windows panes can be replaced for less than the cost of a professional.

First, if you are working on a large window, make sure that it is securely attached to the frame. This task can be done relatively easy and fast with the proper tools and techniques.

If you're ready to begin taking off the old window pane by removing the glazing points of metal that are attached to it. These are tiny metal triangles that act as "nails", holding the window in the frame. They are placed under a bead of glazing putty, which hardens into a solid, moulded wedge that secures the window in place and hides the edges.

After removing the old pane, clean the frame and the wood. Scrape off 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 the same color. After sanding the wood, apply a layer of flax oil. This will help extend its life.

The next step is to measure the dimensions of the window opening. You will need to take horizontal and vertical 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. You can take these measurements to a hardware store or home improvement shop and get 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.