How to repair a broken window glass.
Broken glass and windows are an eyesore and a headache for everyone. Replacing the broken glass can be a good do-it-yourself project if approached carefully.
To begin, be sure that you have the proper glass replacement tools. These can include a glass cutter, push points, glazing clips, glazing putty, a putty knife, chiesel, screwdrivers, a hammer and possibly glass handling suction cups.
Removal of broken glass
In windows it is important to note what you're replacing. You will run into either annealed, common glass or tempered glass or an insulated unit of two panes. You must identify what you're dealing with before taking on the project of replacing the broken glass and attempting the window repair.
The common, single-pane variety of annealed glass is easy to identify. The glass breaks into elongated, pointed end shards radiating from the point of breakage. The single-pane window glass will be the only glass separating the inside from the outside (or the inside from the outlying storm window if you have them). Tempered glass when broken will have shattered into hundreds of small pieces like a car window and may or may not be lying in a pile on the floor. Sometimes the tempered glass will remain in place for a period of time before collapsing, but it will eventually. Identification of insulated glass is usually easy. Insulated glass will have an outer pane and an inner pane and usually only one breaks at a time. If broken, you will be also be able to identify the insulated glass unit by the space between the panes of glass or by identifying the glass spacer that once separated the two panes, which will remain in the window frame.
Common, single pane windows are the easiest windows to repair, Windows with tempered glass or insulated glass will require the assistance of a glass company to acquire the replacement glass. Always replace broken glass with the same type of glass you are removing. Repair your window with the same glass thickness and type.
First, carefully remove all loose pieces of broken glass from the window. The edges of these pieces will be razor sharp and will cut through your skin by simply brushing against them. Next, remove the trim stop that holds the glass in place unless there is putty to the outside of the window. A wood stop will be inside the window and will resemble a narrow piece of trim. Sometimes a chiesel or a screwdriver can be used to pry the edge up and pull the stop off nails and all. You should remove the wood stop while carefully removing the glass held in place by it as you go. Be careful not to break or split the pieces too much, however, much of the time it is unavoidable.
If you have a vinyl window proceed with caution. It is very likely that you have an insulated glass window. The stops on these windows are matching vinyl strips that snap into place against the glass to hold it in place. The stops will either pry loose on one end by pulling up away from the sash, and others will snap out of the frame by prying them towards the center of the window. Also, many vinyl windows come from the factory with either silicone or a strong glazing tape holding the glass behind the stop. This will have to be cut away before the glass can be removed and repaired.
If you have wood or metal windows with putty on the outside, the putty must be chieseled out of the frame without damaging the frame. Remove all of the broken glass and old putty, cleaning the frame to as smooth as possible before continuing.
Once you have the glass and the stop or putty removed, measure the replacement glass size. This will be from the inside dimension of the frame without glass in it by width and height. Subtract at most a 1/4 inch from each measurement for your glass size. This will allow for a 1/8 inch space for moving room all the way around to reinstall the glass. In the very least, your glass must cover your visible opening enough to conceal the edges in the frame when the window is repaired and completed.
Replace the window glass
Once you acquire your replacement glass and the window sash is empty and clean you are ready to complete your glass repair.
In a wood sash, place the new glass in the frame, and use either push points or tape to secure the glass in the frame. Next, replace the stops or prepare to putty from the outside. If you have wood stops you are finished once you have put them pack in place.
In a metal sash, you will have found clips that attach to the frame that held the previous glass in place. You may either re-use the existing clips, use new clips or use glazing tape to hold the glass in place.
In a vinyl sash, affix the glass in place with glazing tape and replace the stops. In a vinyl sash you are finished.
If your sash requires putty, be sure to use the appropriate putty for the application. There is putty designed for wood sashes and a different putty designed for metal sashes. In both cases, pull out a handful of putty from the can and knead it in your hands for about 30 seconds to get an even consistency. Roll the putty into a workable bead or coil that can be pressed into place along the edge of the glass. Finish the putty by taking a flat edge or putty knife and holding it at a 45 degree angle against the edge of the sash and the glass, allowing a triangular area beneath facing the empty corner. Press the putty into place with the putty knife or straight edge with a smooth motion, sliding the tool along the edge of the glass flattening the putty to the contour of the straight edge filling the corner of the exposed glass edge. It will take a few tries to accomplish the right amount of pressure and a smooth motion to spread the putty evenly. Cover every inch of the frame from corner to corner on each edge until you have gone all the way around the window. Scrape and remove excess putty and let the putty set up for two days before handling or cleaning the putty.
You have then repaired your broken window.
