Fixing old sash cords

Q: I didn’t pay much attention to the way double-hung windows worked, until one day when I lifted the sash higher than usual and heard a crashing sound. Turns out the windows were supported by a chain-and-weight pulley system on both sides. Now that window has lost one chain and weight, it is too lopsided to open or close. How can I fix this? — Clay B., Concord, N.H.

A: Double-hung windows use a dependable system with a fairly heavy weight, a rope or chain and a pulley wheel. The chain is recessed inside a groove on the sides of the window sash. The chain then travels upward above the sash and loops around a pulley wheel set into the jamb. In the hollow space inside the frame, the chain is attached to the end of a long, narrow iron weight. This pulley system allows double-hung windows to lift smoothly and easily.

Fortunately, you can access the inside of the frame in older double-hung windows to recover the weight and reattach the chain. Remove the wooden window stop on that side using a utility knife to cut through the paint film and a small pry bar to ease the piece out. Then pull the lower sash out of the frame, removing the sash cord on the other side to free it, and set it aside.

Inside the jamb, you should see a set of screws in the wood, indicating an access cover. Unscrew the cover — you may need to cut through paint again — and remove, revealing the jamb interior and the fallen weight and chain.

Retrieve the chain through the access opening and detach from the weight. Untangle and check for damage. Then feed the chain around the pulley wheel — if it’s stubborn, tie a nail to the chain end with a piece of string as a guide — and lower down into the cavity. Have a friend hold the end of the chain while you reattach the interior end to the weight.

Screw the access cover back into place, attach the lower sash to its sash chains and ease into place. Then nail or screw the window-stop back on.

HOME TIP: Replace pulley chains in double-hung windows with 1/4 -inch nylon rope designed for the job. It’s durable, rarely tangles and much quieter.