How to Replace a Window Sash Cord

Replace a broken window sash cord by removing the window sash, accessing the weight pocket, threading new cord through the pulley system, and reattaching everything in reverse order.

1. Carefully Pry Free the Stops. Use a putty knife or flat pry bar to carefully remove the interior window stops on both sides of the window frame. These thin wooden strips hold the lower sash in place. Work slowly to avoid breaking them, as you'll need to reinstall them later. If they're painted, score the paint line first with a utility knife.
2. Lift and Swing the Sash Free. Lift the lower sash slightly and tilt the bottom toward you. The sash should now swing free from the frame. Have someone help you if the window is large or heavy. Set the sash aside in a safe location where it won't get damaged.
3. Extract the Fragile Parting Bead. The parting bead is the thin strip of wood between the upper and lower sash tracks. Carefully pry it out using a putty knife, starting from the bottom and working up. This piece is often fragile, so take your time. You may need to remove paint buildup first.
4. Locate and Open the Weight Pocket. Look for a small rectangular access panel in the window frame near the bottom, usually covered by a piece of wood or metal. Remove the screws or pry off this cover to reveal the sash weight pocket. If there's no obvious panel, you may need to remove some trim to access the weights.
5. Clear Out Broken Cord and Weight. Pull out the sash weight from the pocket. Cut away any remaining pieces of old cord attached to the weight. The cord likely broke at the pulley, so check there for any remnants that need to be removed. Clean out any debris from the weight pocket.
6. Feed New Cord Through Pulley. Tie a small weight or washer to one end of the new sash cord and feed it over the pulley at the top of the window frame. The weighted end should drop down into the weight pocket where you can grab it. Use sash cord specifically designed for windows, not regular rope.
7. Tie Weight with Secure Knot. Remove the temporary weight and tie the cord securely to the sash weight using a strong knot. A figure-eight knot works well. Make sure the knot is tight and won't slip. Lower the weight back into the pocket, leaving enough cord length to reach the sash when it's in the closed position.
8. Attach Cord to Sash Hardware. Find the groove or hole in the side of the window sash where the cord attaches. Thread the cord through and tie it securely, or use the original hardware if it's still good. Test the connection by gently pulling on the cord to ensure it holds the weight of the sash.
9. Verify Smooth Operation Before Finishing. Place the sash back in the frame and test the operation. The window should move smoothly up and down with the weight properly counterbalancing the sash. If everything works correctly, reinstall the parting bead, then the window stops, securing them with small finishing nails.