So what you are advising him then is to put it over a waterproof membrane. Lots of those out there and none are magic, some just have better marketing programs than others.Google Schluter Systems
Assuming this is over framing, not CMU:
Pool mix (white cement + white quartz or dolomite sand + lime + pigment + optional acrylic fortifier) over fiber-reinforced scratch and brown, on rib lath, over Stego Wrap over framing. 7/8" thickness at least, properly screeded.
Or pool mix over brown on concrete board over stego. Less durable than full mud coat, but requires less skill.
I'm not a big fan of plaster showers over wood framing. Plaster finishes also require maintenance to keep them looking nice, and will still show some age,which most Americans don't like. Plaster showers are great around the Mediterranean, where it's dry and the structure beneath (CMU or older masonry) can absorb a lot of water and not move.
My example is definitely not for immersion. Of course you're right about stucco; I've just upgraded it with a finish coat appropriate for a good shower, rib lath to keep it from cracking for as long as possible, and StegoWrap to deal with the water that gets through the plaster. You could get rid of the pool mix and make it more like concrete than a fine finish, and you could get rid of the rib lath and StegoWrap if you're going over CMU (in which case I would use Hydroban)....
CSFO's example is for containing water, that's 100% constant immersion. I'd imagine a stucco app would work here because, I mean, there are concrete showers, porous stone showers, etc.
As I mentioned in the other post, I haven't done any in a little while - actually we did a tadelakt outside wall last year, but no interior stuff in a couple years.how has the tadelakt been for you? my sister ordered some to play with at one point and has a bunch of it still. impressive set of skills your have there SFO, is this thing common in your area?
Does that mean you'll install panels, then put a finish coat on them? Or pre-cast whole walls?As much as I like this idea I'm re-realizing that precasting gfrc concrete shower panels will give me better results more predictably.