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.
Hang the door in the jamb.
Only shim the top jamb if you re working with a 3 ft wide door and the top jamb arrives bowed from the factory.
Screw the hinges onto the correct side of the jamb.
It s not always necessary to use shims on the top doorjamb the casing will hold it in place.
Make sure it s tight and opening in the right direction.
If you re not steady with your saw you can use a straight edge as a guide.
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.
If you would like to paint repair or alter the door frame in any way now is the perfect time to do so.
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 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.
A new door jamb with decorative trim can make a dramatic enhancement.
Pry the side jambs away from the studs and then pry down the head jamb.
Check the fit before installing a new door and enlarge the opening as necessary.
Allow the glue to cure and drill the pilot holes.
Go slowly and make a long clean cut.
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.
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.
Caulk underneath the spots where the bottom of the jamb and brick moulding will be.
Once again take care not to damage the frame or the wall during this step in the process.
Remove the old door and cut the new door down to size.