Old windows use weights on strings for counterbalance. The weights are inside the walls, and when the string -- called "sash cord" -- breaks, the window won't stay up on its own. If it's just one broken line, the situation is less precarious, but for some reason broken sash cords seem to come in pairs. When we moved in, there were at least five windows with broken sash cords.
How do you repair something you've never seen that's contained inside a wall? It was a total mystery to me, and all the tutorials I found online made reference to an "access pocket" that our windows did not have.
But that made figuring it out all the more satisfying, and I can tell you with confidence that there is no reason to pay a professional to do it for you. If you have the slightest experience with home repair, you can fix your own broken sash cords.
A simple sash cord repair could take you as little as an hour or two, not including the post-op paintwork touch-up. This documentation, however, spans two years, so please forgive the inconsistency of the photos, most of which were taken with a phone while my camera was dead. The photo above is our first-floor bedroom during demolition phase, with the propped window in the background.
Detail of the pulley. When we're done, there will be a cord running over this little wheel. Go to any hardware store and ask for "sash cord," and you'll get a lifetime supply for $7. Oil the pulley if it sticks or squeaks.
Here is where the project starts, with the trim in place. Carefully remove the wide trim (the "casing"), using a hammer and a piece of scrap wood as a wedge. Hammer on your wedge, not your wood trim. Go slow and figure out which direction the nails run, and adjust your technique accordingly.
Remove the casing and set it aside.
Plaster and lath walls. Use your hammer to bash a hole at least two inches wide and about ten inches high. Go slow and keep things under control, and you'll be fine.
The weight will be sitting right there. Fish it out.
Bash another hole up top by the pulley. Disregard the string in the picture above. The routing is wrong.
This is the correct routing. Feed one end of your new line over the pulley and out through the hole.
Tie your new line to a medium sized wrench (or similar object), and drop it back down into the upper hole. Gravity will pull the wrench and the line through.
Retrieve the wrench...
... and tie on your old weight with a knot that won't come undone. Place it back in the wall.
You're going to cut the cord now. Estimate the length you'll need by pulling down on the cord until the weight stops at the top. (For an upper sash, the weight rests at the bottom.) With the line pulled tight, cut off the loose end down where it touches the window sill. Then tie a knot so there's no chance the cord will disappear into the wall.
If the window side channels need paint, this is a nice opportunity to do the job without the cords in the way. Wrap those knots and the pulleys in masking tape, and get it done. (You can disregard that the casing is reinstalled in this photo.)
To finish the project, you need to remove the sliding window itself (the "sash") and attach the cord. In the photo above, note the gap along the right edge of the lower sash. The small "track" of trim has been removed. You only need to take the trim off one side to get the sash out of the frame.
I failed to document this moment in the project, so I went to Hippo Hardware and found a salvaged window for sale to photograph.
Once the window is out, you will see the remnant of the old cord. The Hippo Hardware window just has a slot for a knot. Our windows attached a little differently, but it doesn't matter. Just make your new sash cord look like the old sash cord.
When the sash is resting in the lowered position, you want the counterweight to hang an inch or two from the very top. Attach your cord to the sash, and test your new counterweighted window. Everything slide up and down freely? Cut off the excess cord, and you are done! Time to celebrate with a cup of coffee.
Re-install all your trim, caulk your gaps, fill your nailholes, prime, paint and hang some curtains.
That's how I did it for all of my sash cord repairs, but it's not the only way, and perhaps not the simplest. As the picture above shows (Click to go big and see the weights and J's smiling face), you can also access the weight pockets from the exterior, simply by removing the casing. I suppose this is preferable to smashing holes in your plaster walls.
However, I can think of a number of reasons that I'd rather do it my way:
1: Working from a ladder of any height is exhausting and tedious.
2: With full-time jobs, two kids and Portland weather, finding rain-free daylight hours for home projects sometimes feels like a pipe dream. We did 90% of our renovation after 7 p.m. This is not a project you want to attempt by flashlight. Working indoors with good light, good music, good ergonomics and your tools close at hand (including a cup of coffee) makes for good results.
3: No one will ever see those holes anyway.
The only reason I'd choose to tackle this project from the exterior would be if my interior trim were the original architectural wood in very good, unpainted condition. In that case, I'd think long and hard before hammering and prying on it, yanking those original nails, and filling new nail holes with wood filler that had to be re-stained.
If you find this tutorial helpful, or if you have any questions, I hope you'll leave a comment.
Good luck with your projects!