Sealing villaboard

Hi all.

I'm having a go at converting a study into an ensuite, all seems to be going well but I've ran into something Google and Youtube refuse to help me with.

I am about to seal my villaboard sheets with mud and paper tape, but I'm not sure if I'm supposed to also use this method to seal the wall sheets to the floor (I also have villaboard on the floor which is stuck down to thick chip board) and the wall sheets to the ceiling (I'm tiling to ceiling, no cornices).

Or do I caulk those gaps?

The ceiling doesn't matter I guess but I'd like the floor to be as tight as possible obviously... I will waterproof and all that but I'd like a good backing first.

Thanks!!
Tye

on my ensuite, where blue board met the concrete slab i used fibreglass for the bottom join.

Like a sheet/strip?
How is it stuck down? In the waterproofing membrane?

just lay a strip of fibreglass down in the corners and then use (resin and hardener) and brush it on ensuring you get rid of the air bubbles.