Historically, pocket doors were a common design element in homes. The pair of doors that slid right out of sight into pockets in the wall was a common feature of elegant homes in the 1890s. Over time, pocket doors fell out of favor, probably because they were hard to open and close, noisy, and often came off the track.
Nowadays, however, pocket doors are making a comeback. They're still practical (you don't need to leave floor space just for a door to swing open), and newer pocket door designs are quiet, strong, easy to operate, and seldom jump their tracks.
The major downside to installing a pocket door is the need to have access to the framing around the door to create the pocket that the door slides into. In new construction and renovations, pocket doors are great, but replacing an existing door with a pocket door would mean opening up the walls around the door to install the pocket mechanism, and probably isn't practical. Assuming your door framing is open, here's how to install a pocket door.
Frame the Opening
As with most home construction projects, your first step is to do the framing. For a pocket door, the rough opening will seem gigantic, because you're actually framing for the width of two doors (your framing needs to accommodate the door for both the open and closed positions). Frame your opening to the width the manufacturer of your pocket door kit suggests - usually twice the width of your door, plus 1" - so if you're installing a 32" door the rough opening will be 65" wide.
Also, frame the top of the door opening to the manufacturer's recommended height. This is usually about 85". Be sure the rough opening is plumb and the header is level. If they're not, your pocket door is going to give you trouble all its life.
Install the Pocket Door Hardware
Once you're sure your framing is right, use a hacksaw to cut the pocket door header and track assembly from the kit to length, and install it using the brackets and fasteners supplied with the door.
Reinforce the pocket structure by installing two sets of the pocket door "stiffeners" (thin metal supports supplied with the kit). One set, called jamb stiffeners, is first attached to the header, plumbed up, and then fastened to the floor. Another pair of stiffeners are positioned and attached in the middle of the pocket framing. The instructions that come with your pocket door kit will explain precisely where these stiffeners, called side-split jambs, need to be installed.
Finally, install the door bumper on the stud at the back of the pocket.
Prepare the Door
Pocket door kits are usually designed to accommodate 1 3/8" thick hollow core doors weighing less than 75 pounds. However, any kind of door can be mounted on the proper pocket door hardware. You can even get hardware that will support doors that weigh well over 150 pounds.
Whatever type of door you choose, it's important that you finish or paint the door on both sides as well as the edges before you install the hardware. Remember that the door is going into a wall, so it will be very hard to finish it once it's installed. Plus, finishing the door all around means it won't absorb any moisture and possibly warp after installation.
Mount the doorplates on the top of the door and put the hangers onto the track. Hang the door and adjust it for height and plumb using the built-in adjusting nuts.
Put Up the Drywall
Install the drywall over the framed opening, using construction adhesive to attach it to the framing members. You don't want any nails or screws protruding into the pocket and scratching the door. Tape any joints and finish the seams.
Only a few things left to do First, install the adjustable door guides at the mouth of the pocket - these will center the door in the pocket and keep it sliding smoothly. Now install the side jambs and finally the head jambs. Use screws to install the head jambs last, just in case, so it can be removed if you ever have to take out your pocket door sometime in the future. Finally, install the door casings. Use finishing nails and put some glue on the miters and construction adhesive on the backside of the casing to hold it firmly.
Congratulations, you've just installed your first pocket door.