Shower Waterproofing

Hi everyone - I’m putting in a new “mutant” shower with Permabase walls, mud pan, and Schluter curb (pan not installed yet). I would like to use one system to waterproof the entire shower and was thinking either Ardex 8+9 or Hydro Ban (Unless there is a better option)

Questions:

- Which system is recommended?

- What prep work needs to be done on the cement board joints before applying the waterproof?

- What prep work needs to be done between the mud pan and cement board before waterproofing?

Other details…

- This will have a thick (~3”) mud pan due to installing a FloFX drain flange above slab (cannot puncture the slab to recess the drain assembly due to a radon mitigation system)

- Cement board was chosen over Kerdi board or something similar for stiffness/rigidity. The wall original framing was not plumb/flat. I shimmer the studs to make a flat surface, but did not want to risk buckling or cracking an expensive foam board (don‘t judge the random sheet of Durock, Lowes ran out of permabase…)

Thanks!