From DIYinfo.org
To save space in a corridor or a small room, it may be possible to hang a sliding door over the door opening. But there must be space on the adjacent wall for it to slide back when open. Consequently, furniture cannot be placed against the wall.
Various designs of sliding door kits are available. The job will be easier if you choose one that fits on the wall above the door opening rather than to the ceiling.
If you do not buy a kit with a built-in pelmet to hide the hangers, make a pelmet with softwood battens and a plywood or hardboard fascia, and paint it.
You Will Need
Tools
Screwdriver; tenon saw; plane; chisel; mallet; filling knife; drill and twist bits; countersink bit; masonry bit; spirit level.
Materials
Glue; interior filler; two pieces of 75mm wide softwood, the thickness of your skirting boards and the height of the door opening; one piece of 75mm wide soft¬wood, the thickness of the skirting and a little longer than twice the width of the door; 50mm No. 8 countersunk screws; perhaps wall plugs; sliding door gear; light¬weight flush door; bow handles or door knobs.
Helpful Tip
If you can afford it, buy a new, light, flush door rather than use the old one; otherwise you will have the problem of patching the recesses where the old hinges and lock were fitted.
[edit] Method
1 Unscrew the hinges and remove the old door.
2 Fill the hinge recesses in the frame with scraps of softwood cut to size and glued in place. Make them slightly proud of the surface, and secure them with partly knocked in panel pins until the glue has dried. Then remove the pins and plane the wood down.
3 Lever off the architrave around the door with an old chisel or other lever. Wooden wedges driven between the wall and the architrave can be effective.
4 Fill any holes in the plaster, using interior filler.
5 Screw a length of 75mm softwood (the same thickness as the skirting board) on each side of the door frame between the skirting board and the top of the opening.
6 Screw the remaining piece of softwood to the frame above the door and along the wall as far as the width of the new door. It will be used to support the new door, so use a spirit level to make sure it is horizontal. Put the screws about 300mm apart.
If the wall is made of masonry, use wall plugs. If it is made of plasterboard or lath-and-plaster, you will have to locate the wall studs and drill pilot holes for the screws.
7 Screw the sliding door track to the wood strip. Use the spirit level again to check that the track is horizontal.
8 Screw the hangers to the top of the door.
9 Hang the door and fix the guides to the floor, following the manufacturer's instructions.






