How to Repair a Broken Window

Eleven windows in our house had cracked or broken windowpanes when we moved in. Eleven! In fact, most of those are still broken, because we didn’t get that far down on our to-do list before winter hit, and then it was just too cold to repair them. We did what anyone would do – put a couple of strips of packing tape over the cracks and wait for spring. Now that spring has sprung (sort of – it did snow here on Saturday), it’s time to peel off the tape and fix those broken panes for good. Or at least until a neighborhood kid throws his baseball through one (ala Dennis the Menace).

Luckily, we do know how to fix these as we did a lot of repair to broken storm windows last fall. We have the old removable storm windows that are much like an extra window you just attach over your others for the winter. They’re removable in the summer for increased airflow. The beauty of these old storm windows and wood framed windows is that they’re made to last. Yes, they might break and the counterweights might get stuck, but they’re made to be repairable, unlike many of the vinyl windows on the market with about a ten-year shelf life.

Things you’ll need for this project:
• A broken window (obviously),
• Chisel or Paint Scraper (a standard screwdriver might work as well),
• Window Putty,
• Glazier’s Points,
• Window Glazing tool (helpful, but not absolutely necessary. You can get one of these at any hardware store for around $5, though, so I’d recommend it),
• New glass cut to size,
• Primer and Paint (to match the window frame) OR linseed oil, if you’re working on an unpainted window frame.

So, before you can fix the broken windowpane, you’ll have to remove the old one. Glass panes are affixed to wooden windows with window glazing. The exterior rim of the window is trimmed with a putty-like substance that, when hardened, holds the window glass in place and makes the window airtight. It’s the glazing that has to be removed, then, to get the pane out. You can either chip away at the glazing with a chisel or paint scraper or use a heat gun to soften it a bit before prying it away. We tried both methods, and frankly either one seems fine, as long as you’re not trying to salvage much of the broken windowpane. The heat has a tendency to crack the glass even more, so be careful if you’re using this method. I’d recommend wearing tough leather work gloves to avoid cutting yourself. It’s helpful to start at the edge of the glazing that directly touches the wooden window frame. That way, you’re not applying as much pressure to the glass and have a lower chance of cracking it.

Once all the glazing is removed from the rim of the windowpane, it’s almost ready to come out. You may notice several small metal pins holding the glass in place. These are called glazier’s points, and they do just that – hold the windowpane in place. They’re there to hold the glass steady while the putty dries, creating the lasting hold. These should be removed in order to get the glass out. You can usually pry these loose with your fingers, but you may need some pliers or the flat end of a screwdriver in order to get them out. Generally, there’s only a couple of these per side of the window, depending on how large the windowpane is.

After the glazing and glazier’s points are removed, the glass should come out fairly easy. There may be a small amount of dried glazing on the other side of the glass holding the glass to the wooden frame, but you should have no problem pulling the glass loose from that. If the glass happens to break here, just go back and chisel out any remaining bits.

You’ll want to make sure to chisel out all remainders of the glazing after all the glass is removed to ensure that the wooden frame is completely free of glass bits, glazing, and glazier’s points. You can use the same tool you used to loosen and remove the glazing the first time for this. A stiff wire brush might also be helpful to ensure your wooden frame is as smooth as possible.

After the glass is removed and all the loose bits of putty and debris are gone, you’re almost ready to install the new windowpane. First, you’ll want to make sure to prime and paint the edge of the window frame on which your new glass pane will rest. If you’re working with an unpainted window, linseed oil should be used instead. This seals the wood and keeps it from sucking all the moisture out of the putty you’re about to put down.

Once the inside edge is primed and painted, take a small amount of window putty and roll it into thing strips about the size of a spaghetti noodle. Then, push the “noodle” of putty into the window frame. This will serve as a sort of cushion for your new glass pane. You’ll have to knead the putty first to make it pliable, but this part should be fairly easy.

After the putty is laid down, place your new pane on the window frame and press down to ensure a tight and accurate fit. If all looks well, you’re ready to install glazier’s points to hold the pane in place until the putty is applied. Push one glazier’s point alongside the windowpane into the frame approximately every six inches or so around the pane, depending on how large it is. Our window frames were about 24 by 26 inches, and we used three to four per side. They can usually easily be pushed into place, but you may need the flat end of a screwdriver and a hammer to push them in. Be careful, of course, as you wouldn’t want to break the glass at this point.

Finally, install the putty around the rim of the windowpane. Take small globs of putty and knead them in your hands until they become pliable and soft. Then, roll them on a clean surface (you can use another sheet of glass or even the windowpane your working on) until they’re approximately pencil-sized. This will take some practice to get the right size, but depending on how many windows you’re repairing, you’ll soon get the hang of it. Then press the putty around the rim of the glass. Smooth out the putty using the glazing tool (if you have one) or a putty knife/paint scraper. You’ll want to create a beveled edge. Continue smoothing it until you have a nice slanted edge to your putty.

Lastly, allow the putty to dry according to the directions. This could take several days, so be patient (that’s why you used glazier’s points). Once it’s dry, paint over it to match your window frame, and you’ve got a new window!



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2 responses to “How to Repair a Broken Window

  1. runyanthree

    Geez guys–that is involved! Bill wanted to do that for some of our windows and we nixed that idea. 🙂 Good job!

  2. Pingback: A Year Later « Bungalow Bungahigh

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