I am building a custom 33"x41" walk in shower (and will use your advice on the hand made pan). I need to know - if my slate is only up to six and a half feet on the wall, do I use blue board (mold resistant) for the other foot and a half and the ceiling? This non-tile part will be painted. I'll post some pictures after I find my camera.

thanks

What board are you planing on using for the tiled area?

1/4 inch Durarock, unless the pros tell me otherwise. I am leary of HD/Lowes as the answer seems to vary from store to store. I did go to the USG web site and they lean toward not recommending painting. I see a lot of greenboard recommendations, but they all go against building codes.

You'll need something that is 1/2" thick to match the thickness of your drywall or greenboard, or whatever you use for the rest of the shower. Painted Durock doesn't look very good.

Run the CBU up to the shower head, then drywall up to and including the ceiling. Prime the drywall area then use a good quality paint on top of the primer. That should keep any moisture from getting into the drywall.

I am using the Bulls-EYE 123 for priming the cieling and the drywall down to the Cement board. What is used to join the cement board to the dry wall? I assume the tiles will end on the drywall and silicate sealer will be beaded on the bullnosed edge?

Run your drywall about 1-1/2" below the top of where your tile will end.
Theres no need to finish tape this area. Run a strip of alkali resistant mesh tape over the seam. You don't need to prefill this seam.

Good choice on the primer.