Bifold doors are a practical alternative to the swing-out doors and the sliding doors usually found in homes. They require less clearance than swing doors to open, and unlike the sliding doors installed on closets, bifold ones fold back to expose the entire contents of the closet.
Bifolds are really two doors hinged at the center. They open by folding back accordion-style against the door frame. There are no hinges at the side jambs. Instead, the doors pivot in brackets positioned at the top and bottom corners of the doorway.
Bifold doors are available in either plastic or wood and in two standard heights: 6 feet 8 inches and 7 feet. You can trim wooden doors slightly to fit a smaller frame, but you cannot cut plastic doors.
If you plan to install bifold doors, it is best to buy them in a kit. The kit will include all the necessary hardware: the track, pivot pins, pivot brackets and handles. Also, the doors will come already hinged together.
Before purchasing the doors, measure the dimensions of the frame carefully; then decide whether you need one 2-door unit (two doors hinged together) or a multiple unit consisting of two 2-door units. A single two-door unit is adequate for a standard door frame. The door will fold back to one side of the frame. For wider frames, install two units, one on each side.
If the door frame is a standard size, the installation will consist of mounting the stop molding to the jambs, attaching the slider track to the top jamb, screwing the pivot brackets in the corners and putting the doors in place. Before doing this, however, take the time to check the frame carefully to make sure that it is perfectly plumb and square. Use a level across the top and sides of the frame to see if it is plumb. Check the corners with a framing square and make sure they are at 90-degree angles. If the frame is not square or plumb, the doors will jam when you fold them in or out.
You can adjust a frame that is out of alignment with thin wooden wedges, called shims. First, pry off the trim around the door. This will expose gaps between the jamb and the framing studs.
Insert a pry bar between the jamb and the studs and gently pry the jamb back a little. It is not necessary to pull the jamb off the stud; simply loosen it so you can remove the nails holding it in place. Push shims between the jamb and the studs to adjust the jamb until it is square and plumb.
Secure the jamb with new finishing nails, but leave the heads protruding slightly in case you have to make adjustments when the doors are in place. You may have to wedge both side jambs and the top one to square up the frame.
The next step is to nail the stop molding to the jambs with 6d nails. The molding should be positioned so it fits inside the frame but is flush with the front edges of the jambs. Next, screw the track to the top jamb; the necessary wood screws will be provided in the kit. The distance between the center of the track and the stop molding should be half the thickness of the door plus an eighth inch. Screw the bottom pivot brackets into place on the floor. They should align vertically with the pivot brackets in the track.
Set the doors in place by sliding the door pivot pins into the top and bottom pivot brackets. These are spring-loaded so you can push them back to gain clearance as you maneuver the door over the bracket holes. Next, depress the track guide on the top of the door and slide it into the top track. Now test how the door opens and closes.
When door operation is smooth, finish nailing the jamb, then mount the trim molding around the door frame.
Countersink all nail heads and fill the holes with wood filler. Finally, attach the knobs to the doors.
