How to Replace True Divided Light Window Glass

How to Replace True Divided Light Window Glass

A friend of ours owns an older home that is full of charm and character that only older homes exhibit. Having an older home presents some different maintenance challenges, like to one she asked about last week end. She asked how to go about fixing a broken window pane in the storm door on the rear of her house.


Our friend was in luck, she actually has an old wooden storm door, which actually can be repaired without a lot of trouble. The glass in her door is divided into nine pieces, each of these pieces or sections is separated by wooden trim. This style of door is known as a true divide light panel. Not all doors are built this way, some will have one piece of glass that covers the entire window opening and instead of having wooden dividers between each section, the molding is applied over the glass. A duplicate set of applied molding is applied to the other side of the glass giving an appearance of being true divided light.


On a door or window that has true divided light panels, the glass for each section can be removed and replaced individually, and here is the process for doing just that. On the inside of the panel the glass is normally held in place with a putty that is known as glazing compound.  On the outside of the glass, the widow trim will hold the glass in place.  The first step to removing the broken piece of glass is to remove the glazing compound. The best tool for this is a heat gun, which looks like a hair dryer on steroids. The heat gun is an industrial version, which has a much higher heat setting than your hair dryer, but the concept is the same. 


The first thing you will need to do is to put on a pair of good work gloves.  I would recommend leather. Cotton or garden gloves will not protect you from the sharp edges of the glass that you are working on, so spend the extra couple of bucks and get a good pair of leather gloves. The second thing to do and just as important as the work gloves, it’s to put on a good pair of safety glasses. These will protect your eyes from any shards of glass that may fly up.


Now with a stiff putty knife in hand, take your heat gun and heat up the glazing compound. It will take a couple of minutes to get the compound soft enough so that you can peel it away from the glass. I like to take one added precaution before I get working on the broken glass pane.  If the glass is just cracked, I like to run painters tape over the glass in a crisscross pattern. Put the tape on both sides of the glass. This will help to keep the glass in one piece until you ready to remove it. If the glass is already broken then remove as many loose pieces before you start working on the glass panel.


After removing the glazing compound, it’s time to remove the glazing points. These are small metal triangle shaped pieces of metal that hold the window against the wooden stops. You can use your putty knife to remove these. Once the glazing points are removed, the glass should come out of the opening. This is one place where gloves are a must. Remove all of the broken glass, and then clean up the area under the glass.


Obtain a replacement piece of glass for your local DIY store or glass retailer. The traditional method is to simply reinstall the glass in the door and secure it with glazing points and compound, however a lot of home repair experts now recommend that you first run a bead of silicon caulk under the glass to seal it, and this really makes sense to me.   Stop air infiltration any place you can. One trick that I have learned the hard way, cover the area of glass just adjacent to where you are going to use the silicon caulk with painters tape. Silicon is a real pain, excuse the pun, to remove from the glass. The tape will trap any squeeze out.


Once the glass and silicon are in place, install new glazing points on the inside of the glass. These are easy to install with the flat face of your putty knife. Put at least two points along each edge of the glass pane. Next it’s time to reinstall the glazing compound. Take some of the compound out of the can it came in, and work it in your hand. Work it until you can form a long, pliable snake of the compound, then place the snake like compound onto the window. After you have the compound on all four sides of the glass, take your putty knife and clean up the appearance of the glazing compound. The best method is to hold the putty knife at a sharp angle with one edge riding on the glass, and pull the knife from one corner to the next. Don’t stop in the middle, it’s really hard to get restarted. Have patience, it takes practice to make the finish look right.


And just like that you’re done. Of course if your door is not wooden, then this repair will not work for you. The newer modern doors will have windows that have metal tracks around the windows that are often manufacturer specific in design. Plus most modern glass panel are normally two panes of glass with an inert gas between the panes. This inert gas helps to make the window more energy efficient. Thus the new windows are not normally repairable by the average home owner. You may be able to obtain a new glass panel including the frame from the manufacturer. 


But, if like our friend, you have the older true divided light panes, yes you can do the repair. But maybe this would be a good time to consider replacing the entire door with an energy efficient unit.   Depending on your individual situation, the replacement may qualify you for a rax rebate for 2009.