I suppose it would work. The only issue I see is that the rough texture of the Hardi might tend to collect soap scum, skin cells, shampoo, etc. You might need regular cleaning with a soft bristle brush and a neutral PH cleaner.

I understand personal "style" but there's a reason you don't see Hardiboard in many showers. Stick with something tried and true.

Still needs waterproofing ans attaching the siding would puncture it. There’s no good way to do it. If there were, you’d still end up with it in the shower, which would be pretty horrible on so many fronts.

Shiplap (is that what you mean by "shop lap"?) makes pretty decent barn siding. The real stuff is rough wood.

I don't really understand why anyone would want to use shiplap indoors, or for that matter, a synthetic imitation of it. But then, I don't understand the interest in barn doors in houses, either. :)

To each his own, though. Decorating is a personal thing.

Not to be critical, or to discourage you, but how long do you expect to keep your house? As Avanti suggests, it's hard for me to imagine that a shower made with such a hard-to-clean material would improve your house's value or sales appeal.

I guess it doesn't matter so much if you have the kind of place where most potential owners will have cleaning staff to handle that chore for them.

If you can find a way to attach the finish you want to a wall that's already fully waterproofed, without compromising the waterproofing, it could work. I'm not qualified to recommend a method, unfortunately. Sorry. But good luck!

Yes!