[masraum]

Originally Posted by look 171

Depending on how out of plumb are the walls. I would plumb it enough and shim everything for the jamb and fit the jamb to the floor only if the floor is way out of level. One a 3'-0" opening (assuming?) the floor shouldn't be that bad, 1/4" out? cut one jamb leg slightly shorter and scribe the door bottom for the eye like Milt suggested. Lever the head jamb and use molding to keep it from moving and don't jamb the head jamb up to the header becasue if header settles more (you know it will) it will push on the head jamb and bind up the door

THe floor is probably 5/8" off from level (in this spot).

Originally Posted by Gogar

Pre-hung door? Throw it in the hole and then make plans?

not prehung, making my own frame.

Originally Posted by Bugsinrugs

What is the floor covering now? Plan on changing it? If you are changing the flooring and the floor is some what out of level you can use a self leveler and feather it out. Would make it so the door wouldn’t have to be cut at an angle.

hardwood, no plan to change it. The floor upstairs (which was originally attic space, but was finished out around 1991), is flat like the ocean.