How to Replace a New Door in an Old Frame?
You can install a new door to replace an existing old or broken door in a couple of ways:
You can use a "prehung" door that is previously placed into a finished frame in order to replace the old door and frame, or you can use the existing frame and install a new door into the existing hinges. Both methods require some carpentry skills.
Prehung door installationStep 1
Separate the trim molding around the existing frame, on both sides of the wall, using a pry bar. Tap the bolts out of the hinges, and take the door out. Remove the old frame. Release the screws with a screwdriver or use a pry bar to pull nails to remove the frame.Step 2
Place the prehung door in position to make sure it fits; sometimes the frame sides need to be cut to fit. Pull the door loose out of the frame by removing the hinge pins, and place the door away. Put the frame in place with edges flush alongside the walls. Slide wooden shims under the side frame to secure it in place.Step 3
Place a level at the top of the frame, and modify the shims under the frame until the top is level. Slide shims from both frame sides, so the taper does not move the position of the door. Place the level on the hinge side frame, and slide shims between the frame and wall to get it plumb vertically. Place additional shims at least in two more spots. Plumb the latch side of the frame once the hinge side is fixed.Step 4
Connect the frame to the wall with 3" screws with a drill once the frame is level and plumb. Drive screws into all shims to fasten them; drive screws right into the wall where there are no shims installed. Clip the shims with a utility knife. Set the door on the hinges and secure it with the pins. Place the trim molding on both walls and connect them with finish nails.
Replacing a door in existing frameStep 1
Separate the hinge pins, and remove the old door out of the frame. Place the old door alongside the new door, and hinges. Connect braces to keep the two doors together. Mark if there are any adjustments required to make the new door fit into the current frame. mark the hinge positions on the new door, using the hinge from the old door as a guide.Step 2
Cut the new door as required with a circular saw to cut through its top or bottom, furthermore, if any minor adjustment is required you can use a plane to correct. Insert the trimmed door in the opening to ensure it fits, and do any size modifications required.Step 3
Mortise the hinge positions on the new door. Use a hammer and a chisel to pierce around the hinge contour, next chip out wood inside the hinge place with the chisel. This requires precise and tedious work to create the hinge area match. You can work with a router if you are comfy with that machine to rout out the hinge location.Step 4
Connect the hinges for the door, using the old hinges or new ones. attach one side of each hinge to the frame, and the other side to the door. Place the door on the hinges, and connect the door to the hinges with the hinge pins. Adjust the door with the current latch plate on the frame, and mark a place for a doorknob.
Drill a hole into the door with a hole saw, normally 2 inches in diameter, and connect the new doorknob. Cut out wood for a latch plate using a chisel, the same way you did the hinges, and screw in the metal plate in position.