How to Replace a Box Window Sash Cord

Do you live in an old home with the original sash windows? Are you currently finding workarounds to prevent them from slamming shut? Good News! There’s an easy way to fix this problem by replacing the window sash cords. Not all vintage windows are the same so let’s focus on how to repair a lower sash for a double-hung box sash window.


  • Utility knife
  • Pencil
  • Tape measurer
  • Molding pry bar
  • Hammer
  • Blued carpet tacks
  • Makita XNB01 nail gun
  • 18gauge 1″ brads
  • Screwdriver
  • 50ft sash cord, recommend 6mm marine cord
  • 100 grit sandpaper
  • Rags
  • Nail gun
  • Paint scraper
  • Masking tape
  • Spray lubricant
  • Candle wax
  • Decorators Caulk
  • Paint brush
  • Primer paint
  • Matching window paint color
  • Tarp
  • Mask

Parts of a Box Sash Window

  • A double-hung window has two sets of counterweights which allows for both the top sash (upper framed window) and bottom sash (lower framed window) to open.
  • Cords, weights, and pulleys. You see rope, but the correct term, is sash cord. A box sash window opens and closes by the weight of the sash against weights (cast iron or lead) that are attached to the cord and passed over a pulley on each side. The weights go up and down in a box that’s concealed within the window frame.
  • Stop beads are the thin pieces of wood trim that boarder the inner window frame and prevent the sash from falling out and at the same time creates a straight guide for the sash to glide up and down.

Prep Area

  • Remove any furniture, rugs, and decorations near the window.
  • Drape tarp on floor for protection and to contain dust and small material particles.
  • Lead paint might be present with older homes. Wear a mask.

Disassemble the Sash

  • With utility knife, carefully score along the paint joints between the stop beads and the box frame.
  • Using the molding pry bar, gently pry the stop bead towards the center of the window, removing it from the window frame.
  • De-nail the stop beads and set aside

Remove Sash Window

  • Cut the cord above where it’s located from the bottom sash window and slowly allow the counterbalance of the weight to pull the cord up to the pulley allowing the weight to be lowered. It’s highly recommended to replace both sash cords.
  • Lift the sash window up and out of the box frame and remove any sash cord that’s attached. Cover and protect the glass and set safely aside.

Remove the Access Panel and Weights

  • Usually cut into the inside of the box lining are removable pocket panels. These will need to be removed to access the window weights. With utility knife, score along the paint joints and then gently pry them out. Some are screwed in rather than nailed, so you might need a screwdriver. Set aside.
  • Reach into the pocket and pull the window weight out, along with the original sash cord which will be tied to the weight.

Prep the Sash Window and Box Frame

  • With a scraper, remove any paint build-up along the outer edges of the sash and inner surfaces of the box frame. Sand smooth and wipe clean with a rag.
  • Apply spray lubricant on the pulley bearings so they roll smooth and silent.
  • Prime and paint the inner window box frame and sash.

Add New Sash Cord

  • Feed the new cord into the pulley and down and out through the pocket opening and then securely tie it to the window weight.
  • Slide the weight back into the window box and let it rest on the bottom.
  • Pull the cord, eliminating any slack and then cut it slightly past halfway down the frame. Recommend tying a temporary knot at the end of the cord to prevent it from slipping over the pulley.
  • To reattach the cords evenly on both sides of the sash, set the sash on the windowsill and tilt it slightly forward. Untie the loose end knot and pull the cord so the weight is about an inch from the top of the pulley and temporarily nail the cord to the box frame, making sure the nail head is protruding so you can easily remove it. This will hold the weight up so you can attach the cord to the sash.
  • Your cord is either nailed into the sash groove (using blue carpet tacks) or the cord is threaded and then tied into knot, flush in the hole on the side of the sash.
    • TIP: If the cord gets bunched up while trying to push it through the side sash hole, wrap a piece of masking tape around the end of the cord into a pointed tip.
  • Remove the temporary nails suspending the weight and let the sash slide into place.
  • Test the sash by gliding it up and down, adjusting cord length if needed. If sticking, spray lubricant or rub candle wax along the sash edges and track. Once satisfied, cut off any extra cord.

Install the Stop Beads

  • Nail in place the stop beads where they were originally. These need to be installed close enough to the sash to prevent it from rattling, but not too close which would restrict it from moving up and down.
  • Apply decorators caulk to seal any gaps between the stop bead and window box.
  • Check to make sure the catches and locks line up and function properly.
  • Once the sash is completely installed, paint the stop bead and areas that need touch up.
  • Operate the sash while the paint is drying to prevent the paint from sealing it shut.
  • Once paint is dry, apply a coat of lubricant spray along the track.

Watch the Video

Unfortunately, some old windows cannot be saved due to dry rot, bug infestation, or water/fire damage and must be replaced with new windows. If you’re looking for new windows, PARR Design Center specialists can help you select energy efficient performance windows from an extensive collection that will perfectly reflect the architectural features of your home.

Shannon Quimby is an internationally acknowledged salvage designer.