If you have more than 3 16 of an inch to remove you can use a circular saw to do so.
Installing new interior door jamb.
Any changes to the door frame should be made before installing the new door.
Go slowly and make a long clean cut.
Pry the side jambs away from the studs and then pry down the head jamb.
Place the door in the jamb and fasten it to the hinges.
If the holes on your new hinge plates don t match the holes in the screw holes in the door jamb drill pilot holes for the new screws.
If you re not steady with your saw you can use a straight edge as a guide.
Make sure it s tight and opening in the right direction.
Unless you are installing a prehung door you ll need to trace the outline of the hinges on the jamb and cut an indentation using a router or utility knife.
Check the fit before installing a new door and enlarge the opening as necessary.
Caulk underneath the spots where the bottom of the jamb and brick moulding will be.
If the holes in the jamb are too large for the screws use wood glue to secure a short portion of dowel tightly in the hole.
Once you are satisfied with the fit of the door remove it and apply several thick beads of silicone caulk to the bottom of the doorsill.
Allow the glue to cure and drill the pilot holes.
Once again take care not to damage the frame or the wall during this step in the process.
Hang the door in the jamb.
A new door jamb with decorative trim can make a dramatic enhancement.
Only shim the top jamb if you re working with a 3 ft wide door and the top jamb arrives bowed from the factory.
And on new homes and additions walls can compress as they settle and push down on the top shims causing the jamb to bow down.
If you would like to paint repair or alter the door frame in any way now is the perfect time to do so.
Screw the hinges onto the correct side of the jamb.