Although hollow doors are popular with many homeowners because they are so easy to install, they do have one major drawback: they are more fragile, therefore tending to break much more often than solid core doors. A hollow door can only take so much abuse before natural wear and tear degenerate into outright disrepair, so what do you do when your hollow interior door has been damaged beyond all restoration?
Determine What Needs to Be Replaced
When door replacement becomes necessary, the first thing you need to do is to check the frame and make sure there is no outstanding structural damage requiring it to be replaced as well. Replacing a frame can be a tedious and time-consuming process, however, installing a new door into a damaged frame can cause even more problems in the long run.
So, when checking a wooden frame for existing damage, do a thorough inspection for rot, moisture damage, and any seams or cracks showing in the wood. When checking a metal frame, be sure it is not rusting or warped out of shape. Be sure the hardware reinforcements are sound--checking the welds, hinges, and hinge reinforcements. If any of these areas appear to be damaged or unsound, a new frame is probably necessary in order to ensure proper hanging of your new hollow door.
Remove Damaged Door
Stand on whichever side your hinges are located. Working your way up from the bottom hinge, remove each hinge pin carefully--tapping stubborn pins lightly to loosen them. In order to prevent injury, have someone hold the door for you as you remove the final pins.
Size New Door
Lay the old door on top of the new door. Trace the outline of the old door onto the new one using a carpenter's pencil. Plane new door to size, making sure there will be 1/16 of an inch around the sides and top, as well as a 1/2 inch at the bottom for frame clearance.
Lay the old door back on top of the new one and mark the positions where the hinges should be attached. Chisel shallow recesses for the hinges, first outlining with the chisel, then chiseling out hinge-deep spaces. Use the chisel on a low angle to prevent digging deeper than necessary. Scrape off any remaining wood. Using the original hinges if possible, place the hinges and make sure the hinges are level with the door. Use the drill to screw pilot holes and attach hinges to the door.
Install Door Knob and Latch
If at all possible, reuse the original doorknob and latch as well to make things easier. Mark off all positions by taking measurements off of the old door. Paint the new door if necessary, making sure to paint the top and bottom of the door as well to block off any moisture from setting in.
Hang the Door
Check the door for fit and be sure there are no loose hinge pins. Check swing and closure, making adjustments as necessary.