Window Blind Repair

Window blinds can sometimes be repaired. This Fix-It Guide on window blind repair tells how a window blind works, what often goes wrong, how to identify a window blind problem, and what parts and tools you will need to fix it. It then gives simple step-by-step instructions for how to replace a tape or string ladder and how to replace a roll-up blind cord.

How Does a Window Blind Work?

Window Blind Repair

Components of a typical window blind operating system.

A window blind is a slatted window treatment that can be adjusted to admit varying amounts of light. Window blinds include venetian, mini, micro, and vertical blinds. They all work in about the same way. They all work in about the same way, with materials ranging from wood blinds to fabric, and more. A tape or string ladder holds all the slats together. A cord or wand connects to a pulley in the headbox. The pulley uses a worm gear to rotate the tube and simultaneously change the angle of all slats. A lift cord threads through each slat and over a pulley at the end of the blind. Pulling on the lift cord raises the blind. The lift cord is adjustable so that the blind raises and lowers evenly. A vertical blind works in the same manner except that the blinds are vertical rather than horizontal.

A roll-up blind is a combination of a venetian blind and a roller shade (see Window Shade Repair). A roll-up blind has slats and pulleys that move only up and down; there is no tilting mechanism.

Fix-It Tip

One of the main advantages of vertical blinds is that their mechanism doesn’t have to pull the weight of the blinds up and down. That means there is less stress on the mechanism. And that means they last longer with fewer repairs.

What Can Go Wrong with a Window Blind?

The tape or string ladders that hold a blind together can break. A blind can stick going up or down or may not go up evenly. More serious problems may require a professional or even replacement.

How Can I Identify a Window Blind Problem?

  • If the tape or string ladders on the blind wear thin or break, you can replace them (see below).
  • If the tilting mechanism balks, look for cord threads or dirt in the worm gear and clean it out.
  • If a roll-up blind cord fails, you can replace it (see below).

Fix-It Tip

When buying a new window blind, purchase an extra set of tape or string ladders or cords for it at the same time. You’ll eventually need them. To make sure they don’t get lost or forgotten, you can tape the package to an unseen edge of the blind. Alternately, have a replacement-part drawer or box where you keep such things.

What Do I Need for Window Blind Repair?

Replacement parts are available from the manufacturer and aftermarket suppliers and from local window treatment stores and larger home centers. You need only a few tools to work on window blinds, including these:

  • Screwdrivers
  • Wrenches
  • Scissors

What Are the Steps to Window Blind Repair?

Replace a window blind tape or string ladder (varies by model):

  1. Remove the blind from the window and place it on a flat surface.
  2. Remove the clips that hold the strings or tapes to the bottom bar.
  3. Remove the end caps and slide apart the bottom bar to expose the ends of the lift cord and ladder tapes.
  4. Remove the knots through the keyhole openings to free the lift cord. Undo or cut the knots to remove the bar.
  5. Pull the adjustment loop until the ends of the tilt cord reach the headbox.
  6. Make a knot in the lift-cord ends so they cannot pass through the headbox.
  7. Pull the slats from the ladder tapes and undo the tapes. Fold over the ends of the new tape, and staple them to create a hem. Loop the hem over the bars or clips.
  8. Remove the knots in the ends of the lift cord. Run the new lift cord through the headbox along the same path as the old cord.
  9. Thread the tilt cord through the slats, feeding it along alternate sides of the tape rungs.
  10. Attach the ladder tapes and lift cord to the bottom bar.
  11. Install the equalizing buckle over the adjustment loop and adjust it for evenness.
  12. Re-hang the blind.

Fix-It Tip

Venetian blind service can be very expensive, especially if you don’t have an experienced service person nearby and must return the unit to the factory. A $1 cord may cost $75 to install–unless you do it yourself.

Replace a roll-up blind cord:

  1. Cut the knots above the headbox and remove the old cord, saving the buckle.
  2. Hang the blind to full length.
  3. Feed the new cord through the headbox and knot it.
  4. Drop the cord down behind the blind and pull it underneath to the front.
  5. Feed the cord up through the blind, through the roller pulley, across the headbox, and through the locking pulley.
  6. Bring the cord back through the pulley, down the front and up behind the blind. Knot the cord at the top.
  7. Slide the adjustment buckle over the loop and adjust it.