Installing PVC shower walls close to the door but my jamb is way too deep - what now?

I ran into basially the same thing a couple years back with a tub surround that went direct to studs. The doorway next to it had been furred out with stacked drywall to cover a too-shallow jamb situation in reverse. I fought it for a weekend trying to make trim work, then just ripped the whole door out and put in a new prehung with the correct jamb width. Best call I made on that whole job. On the hallway side, the casing is not relly tied into anything structural. It's just finish nailed to the jamb and the wall. You pull the trim, cut the shims behind the hinges and latch side, and the old jamb comes out in pieces. A recip saw between the jamb and the studs makes quick work of it if the nails fight you. The only thing to watch is the casing on the hallway face. If it's in decent shape you can usally reuse it, because the reveal and miter geometry doesn't change much when the jamb sits flush with the wall instead of proud of it. If it's beat up, buy new casing and it's a non-issue.

When you order the new door, tell them the finished wall thickness, not just the stud depth. With 2x4 walls and half inch board on both sides, you're in the standard 4 and 9/16 jamb territory, but measure your actual buildup anyway. If the panel edge plus any adhesive or shim lands a hair proud of drywall, a slightly wider jamb is easier to live with than one that's short. As for shimming the panels out to meet the deep jamb, I'd skip it. Getting a waterproof assembly to float off the studs by that much is asking for trouble at the seams, and a big chunky trim leg bridging the gap always looks like a patch job. Since your gap to the door opening is only a few inches, the panel edge trim and the casing are basically going to collide visually anyway. Clean flush wall, proper jamb, normal casing. That's the version that looks like it was built right the first time.

That two inch buildup doesn't surprise me one bit. Half the houses I've worked on around here had plaster and lath, which runs way thicker than drywall, so jambs sitting proud of the wall were just how things were done. The other fix nobody thinks of is going the opposite direction with the wall itself. Fur the whole shower wall out with strips of the right thickness and bring the finished face out to meet the jamb instead of chasing the jamb back. Costs you a couple inches of floor space in a small bath, but the panels mount solid to something flat and the trim detail stays normal. Just check what's in that wall first, I've seen supply lines and old galvanized pipe runs hiding in furred out shower walls more than once.

Reading this and realizing my upstairs bathroom probably has the same thing going on, that chunky trim strip next to the shower that never looked right. Now I know why. I'm trying to picture the swap out in my head though. When you take the old frame out, does the door come off the hinges first and then the frame comes out around it, or does the whole thing lift out together? I've never even taken a door off before so I might be way overthinking it.

Following along here because my situation is sort of the mirror image. My shower surround is fine but the closet door off the hallway sits proud of the wall by about an inch and a half, and the trim guy just buried it in layers of caulk and paint for years. Never understood it untill reading this thread. One thing I keep second-guessing when I measure for the replacement, do you count the thickness of the finish surface on the wet side too, like the panel itself, or just measure the drywall face? Seems obvious but I'd rather ask than end up with another jamb that's short by exactly the amount I forgot about.