For the past few weeks, I have been explaining how to repair a broken window glass in your home. But what if you have double pane windows? The process is the same? Well, more or less, except for a couple of variations. So, let’s go over the single pane repair process and I’ll point out the differences from dual pane windows.
When we start talking about double pane windows, one of the first things that comes to mind is vinyl window frames rather than aluminum ones. When it comes to double pane windows, you can have either aluminum or vinyl frames, depending on the year the home was built. Double pane glass became popular in the 1980s, but vinyl frames didn’t really catch on until the 1990s. So if your home is less than 10 years old, you probably have vinyl framed windows. . In any case, I will discuss the differences. Let’s say you have an aluminum-framed, double-pane sliding window. The procedure for removing the opening frame and sash glass is the same as for single pane windows.
The differences are, firstly, that the glass fits into the frame about twice as much as the single pane window. The single pane window glass was driven 1/4 “into the surrounding rubber. The double pane is generally inserted 1/2” into the rubber. So if both pieces of glass have been broken, you will have to order a new IGU (insulating glass unit) from your local glass shop. They are going to want to know the width, height, overall thickness, and possibly the thickness of the individual glass. The best way to get the dimensions is to measure the width and height from rubber to rubber, jotting down those numbers. Next, remove the panel from the opening and place it on a table as we did with the single-pane window. Remove the screws from the opposite corners and pull out the frame. You will be able to see how far the glass goes into the surrounding rubber. If it is 1/2 “, then you want to add 1” to the width and height you measured earlier (1/2 “by two sides = 1”). Next, measure the overall thickness of the unit by removing the rubber from the edge of the glass.
Usually this dimension is 1/2 “, but not always. There is a metal spacer that divides the two panes of glass. Make a note of the color so you can request the same color on the new IGU. It will be silver or bronze . If you want the same spacer size, you need to provide the glass shop with the thickness of each piece of glass in the GUI. If the above unit has 1/8 “glass on both sides, and the total thickness of the unit is 1/2 “, then they’ll use a 1/4” spacer. If the glass is 3/32 “on both sides, they will use a 5/16” spacer. If you don’t mind matching the spacer thickness, you can order the thicker 1/8 “glass and they will automatically use a 1/4” spacer.
When you get the new IGU home, the installation is the same as the single pane window. Now what if only one side of the GUI has been broken? Many times the outer panel will break, but the inner panel is fine. You can order a brand new IGU like we just did or if you are the adventurous type, you can order just the one pane of glass that was broken and replace it. I’m going to explain how to do it, then I’m going to tell you the things that can go wrong. After you have removed the window pane on the table with the surrounding frame, you will see a black rubber-like substance around the edge where the spacer is applied. This is a butyl sealant and you have to separate the broken glass from this butyl. The best way to do this is to take a utility knife with a fresh blade and break the butyl where it meets the broken glass. Next, take a new hacksaw blade and push it into the area where the butyl separated from the glass. You don’t want the hacksaw blade to be attached to a hacksaw. Using your hand, saw from side to side as you go around the edge of the glass. This should allow you to remove the glass.
Once this is done, place rags on the good glass piece to catch any debris and scrape the surface of the spacer that will be in contact with the new glass. Use a spatula. Then remove the rags and debris. When you are ready to put in the new glass, clean the inside of the good glass that you did not remove. Remember, once you install the new glass, any debris or finger marks on the inside will be permanently sealed. So, clean it really well and check it from all angles. Do the same for the side of the new glass that will go into the IGU. Next, apply a thin bead of clear silicone around the entire perimeter of the spacer. Place your new glass on the spacer and press with your fingers to adhere the glass to the silicone around its perimeter. Next, approach from the side and run the silicone around the side where the glass and spacer meet. Cover the window opening with something for 24 hours. You don’t want to touch the IGU for 24 hours. Silicone needs to cure. After 24 hours, you can assemble the unit and install it back into the opening.
There are a couple of things that can go wrong. The first is leaving marks on the inside of the glass. Once you seal the glass, you can’t clean what’s between the panels. The other thing involves condensation between the panels. If you have even the slightest break in the silicone seal around the glass, you will likely start to see moisture form as soon as the nights get cold and the days get hotter. You will have to decide if you are confident enough in your ability to do the job well, or if it is better to pay the extra money to have it done for you. Just because you pay someone to do it doesn’t mean you won’t have the same problems. The difference is that they have to guarantee their GUI for a minimum of 1 year. I have received many units over the years that had marks between the glasses. The beauty of this is that the manufacturer can’t argue with it, because no one else could have done it except them.
Okay, what if the window frames are vinyl instead of aluminum? Well the main difference is that the glass in a vinyl window no longer has the rubber gasket around the edge. It does not remove the screws from the opposite corners and separates the frame from the glass. What they do is put silicone or a double-sided tape on the edge of the frame where the glass rests. That’s what holds the glass in the frame, then they snap a stopper on all four sides of the glass. Therefore, you must first remove the stops, then flip the panel over and break the seal that holds the glass to the frame with a utility knife. Wear gloves during this procedure. If only one side of the GUI breaks, don’t even think about repairing just one side. You will never get that IGU out of the frame without breaking the other piece of glass in the process. But, on the plus side, you can remove the bumpers without taking out the panel if it’s a slider. You can then measure the dimensions of the glass and order the new IGU. That way, you eliminate any need to temporarily cover your window. The same is true for the stationary part of a slider or an image window. Before installing the new GUI, be sure to clean the edge that had the tape or silicone and apply silicone or tape. Either one will work.
You will find that replacing a GUI in an aluminum framed window is much easier than a vinyl window. But in any case, you can do it yourself and save a few bucks.