Saturday afternoon we ripped out the old bathroom door, which was less traumatic than I expected.. Didn’t really do any damage to the walls removing the trim and ripping out the old door jamb/frame. It seemed like everything was going to be peachy, I nailed the small lengths of 2×4 we purchased into the opening to make it a standard-er size, we started attaching the jamb to the frame and making sure it was square, level, and plumb. We nailed it in on the hinge side in two points, and then shimmed it out on the lock side to give it a test run… And the door struck the jamb at the top lock side of the door. Not only that, but I drove the nails in all the way, so we had to mar up the jamb getting them back out. We playedaround with raising the sides and all kinds of things, but no matter what we tried even though the jamb was square/true/plumb/everything it just didn’t matter. We worked on this whole project for about 5 hours and eventually gave up for the night.
Sunday, we procrastinated as long as possible and started anew. We were just about to start when Corinna had the flash of genius to call her stepfather for advice. He is retired now and doing lots of the construction on the addition to her parents’ home in Michigan. We mentioned that we padded out the space to make the opening “the right size” with six short pieces of 2×4. We explained that the old 2×4 that formed the hinge-side of the existing frame was completely cockeyed and we were using shims to correct for it. He provided the (now obvious) suggestion of getting a single 80″ 2×4 to run the entire length of the hinge side, and shim that as necessary to make sure it’s plumb, etc. Using one long board eliminates discrepancies in plumb/true/squareness between the 3 separate pieces of 2×4. He also suggested using screws instead of nails, because you have more fine-tuning available by tightening/loosening the screws, plus if you screw up you can easily back them out.
With this knowledge in hand, Corinna ventured out to Home Depot (knowing how much I hate going to that store), got the 2×4, we had it up and shimmed out in 20 minutes, and less than an hour later the door was hung and swinging freely.
So I guess the moral of this story is that installing a pre-hung door probably IS easier than fitting one into an existing jamb if you know what you are doing and do appropriate prep work.
Update: Re-edited this to remove some nonsense sentences (I “repurposed” this text from an email I sent to my dad).