I'd buy a firebglass base. Then I'd use green board drywall and mapelasic HPG. The HPG is roll on rubber membrane and has a longer warranty than kurdi, it's cheaper and easier than the kurdi matting for the walls and less painful to install tile over.
Don't use cement board. If anyone tells you you shoud or it's code they are stupid and don't have a clue.
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It doesn't have to cement board if it's water proofed properly. The blue stuff in the photo is the HPG and I've never had a failure. The problem with cement board is it is very difficult to work with and nearly impossible to get it flat when the studs are perfect. It also falls apart when screws get too close to the edge. It's also impossible to trim and adjust if you don't get the cuts perfect, drywall doesn't have this problem. After the tile is done I will also paint this stuff around the shower valve, shower head outlet, and tub spout. You can water proof a cardboard box with this stuff.
I use fiber tape or mesh tape with thinset where ever there's tile, and drywall mud where ever there is paint. Like I say, the HPG roll on stuff comes with a 25 year warranty. 2 coats in the corners and along the top of the tub, one to two coats everywhere else, 3 coats if it's a steam shower or shower base that's going to be tiled. This stuff will water proof anything.Sorry I should have said fiberboard or whatever it's called. I remember Durock from back in the day, but know there's better stuff now that's presumably a lot lighter and less brittle..
I assume the stuff in your picture is that roll-on waterproofing membrane stuff (can't remember what it's called at the moment).
Edit: Whoops missed your first post. I had thought aquaboard wasn't recommended anymore tbh, but haven't looked into it in a while. Not a lot of showers building refineries and chemical plants
I'll definitely replace the valves, shower heads, etc when I get to it. When you're using aquaboard and that roll on membrane, I assume you still mud and tape your aquaboard as normal, or do you just caulk the seam that'll be under the membrane?
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