Adding slats to wood, faux wood, aluminum or vinyl blinds allows homeowners to extend the blind's length. It is possible to add slats to a blind only when unused ladders exist at the bottom of the blind. This is because the blind slats sit on the ladder strings, which work in conjunction with the tilt wands or strings and lift cords, and enable the blind to work properly. Slats most often will be added to a blind when some have been removed previously to fit a shorter window and the blind strings were not cut.
Locate the stopper or plug underneath the blind's bottom rail. Gently pry the stopper from the bottom rail using a flat head screwdriver. The blind should be hanging when lengthening it to ensure that the strings hang evenly.
Untie the cord on each side of the bottom rail and slide the bottom rail off of the blind strings.
Allow the strings to fall freely and undo any tangles or loops that may have occurred while the unused strings were gathered at the bottom of the blind, above the bottom rail.
Add one slat for each set of ladder strings, one at a time. Leave the bottom set of ladder strings empty to reattach the bottom rail.
Thread the blind strings in the route holes in each blind slat. It is best to alternate from the left to the right side of the blind when inserting the strings. Continue to string all slats using this method.
Place the bottom rail into the last ladder string and thread the cord through the hole in the bottom rail. Let the strings fall, untied, to ensure that the blind strings are hanging evenly and the bottom rail hangs straight before securing the strings.
Tie off the strings underneath the bottom rail carefully on both sides of the blind strings. Replace the stopper in the bottom rail. Cut off any excess cord using scissors, but only after tying off the strings. Some blinds will require that you place the end of the string in a notch in the bottom rail. Other blinds may require that the string fit through a hole in the stopper before snapping the stopper back into the bottom rail.
Use the pull strings on the blind to ensure that the blind has been restrung properly.