Bathroom stepup

[Cgas]

Hi just after some advice re bathroom stepup
After looking at some ideas we've decided we're gonna have freestanding bath but raised with stepup and spots set in the wood, just curious as to what to use, we're looking at a floorboard effect, but obviously the floor may get wet so just curious as what to use, pics below as an idea
The step up with the bath;

The boards I'm looking at using;

Not fussed with cost, just want decent quality that's not gonna cause issues obviously cos it may get wet and should you treat it ? Etc, any advice appreciated! Tia

 

[foxhole]

What do you have currently? is this a renovation or new build?

 

[Cgas]

Renovation mate, it's a void under the floor, room is 2m x 4m, all ripped out at the mo, rooms just been skimmed and I've blocked a window up so its just a single window as it limited space as it was before. Just a bog standard suit came out. Minging to say the least

 

[Cgas]

So essentially my plan is to build a frame onto the current ply flooring so raise the height then board over with boards and either seal or paint unsure on finish yet, freestanding bath with over the top taps, tiled behind the bath wall (width ways), the opposite end of the bathroom will be a walk in shower (again tiled width ways) and somewhere in the middle will be a wc/sink unit (far wall) with a rad next to the door by the shower. If that makes sense. Will do a pic tomo for reference.