Although bifold doors come in different designs, the method of installation is the same. It’s a good idea to read the instructions that came with the bifold doors before you begin. Generally the doors are 80 inches tall but can be cut down to fit. The height of the door opening should be two inches higher the length of the doors to allow enough clearance for the track and the rest of the hardware. bi fold doors has some nice tips on this.
Start by marking the top of the opening with a pencil and line up the track. Mark and pre drill screw holes. (Use a drill bit that is smaller then the screw itself ).
Position the pivot brackets (inside the header track ) 3/8 inch away from the end of the opening.
Line up the pivot bracket with the header track. (You can use a plumb bob or lay a carpenters level against the side frame and make a mark at the floor and align the bottom track. I always take the measurements of where the top track will line up and transfer that measurement to the bottom where the pivot bracket will be installed).
If the floor is covered with carpet, you will need to use a wooden pad underneath the bottom pivot bracket. Cut away the carpet just enough to fit the wooden pad and fasten it down to the floor.
If it’s a cement floor, use adhesive especially made for gluing to cement. Let the adhesive set for 24 hours, line up the pivot bracket with the top track and fasten it to the wooden pad.
Once all the brackets are lined up with each other and in place, you can hang the bifold doors by simply folding the doors in half and fitting the guide pin in the upper track. Next, lift up the door and fit the adjustable pivot into the pivot bracket at the bottom of the door opening.
Repeat the last steps for closets with four panels.
Install the doorknobs at a height where it is most comfortable to reach. Don’t install the doorknobs too close to the edges.
If the opening requires four section bifold doors, you will need to install alignment brackets on the back side of the two middle doors. (Approximately 16 inches from the bottom of the doors). These brackets will interlock and keep the doors aligned with each other.