How to Replace a Sash Cord

Step by Step
1. Remove the sashes. Use a utility knife to score the paint between the jamb and the wood strips that hold the sashes in place, then remove the strips with a pry bar. Be patient: if you're careful now, you can minimize the filling and painting you'll have to do later. Next, pull out the lower sash. It should slip right out, but if it doesn't, score between the sash and the jamb with the utility knife, and loosen it gently with the pry bar. Remove any remnants of the old sash cords still attached to the sides of the sash.While you have things apart, you might as well repair the upper sash, too. If it's stuck, as it may be after years of disuse, score between the upper sash and the jamb with the utility knife. If it still doesn't budge, go outside and score around the window's exterior.If that fails, remove the parting strip, the wood strip that separates the upper and lower sashes. Again, score the paint with the utility knife and pry out the strip, working up and down its length so that it doesn't bend too sharply and break. If you do break the parting strip, however, don't despair; most lumber yards carry replacements.

2. Find the sash weights. With the jambs exposed, find the access panels on each side. These house the cords and the sash weights, which look like the pendulums on a grandfather clock. The panels may be painted over and even nailed or screwed in place, so run your hand over the lower portion of the jamb to locate them. Remove any nails or screws, and score the panels' edges with the utility knife to free them from their paint-prison. Lift out the sash weights and remove any bits of old sash cord still attached to them. Then check that the pulleys near the top of the jamb move freely. If not, scrape away any paint that may be binding them, and lubricate the pulley wheels with WD-40™.

Before attaching new sash cords, remove any paint encrusted on the sashes, wood strips or jambs. To help sashes glide more freely, you can also rub a candle along the jambs. When that's done, it's time to reattach the sashes.

3. Attach the new sash cords. Use braided nylon sash cord for this project it stays supple and significantly outlasts cotton. Feed each new sash cord over the pulley from the top, down through the cavity behind the jamb and out through the access panel opening. Tie the new cords to the weights. Then tie knots in the other ends of the sash cords, and push the knotted ends into the slots cut into both sides of each sash, as shown in the animation.4. Reassemble the window. First put the upper sash back into place and nail the parting strip into its slot. Then replace the lower sash, and nail the strips that hold it in place back onto the jambs. Use 4d galvanized finishing nails in both cases. Avoiding using glue that way, you can remove the pieces if you need to. After making sure that both sashes raise and lower smoothly, replace the access panels.