Advice needed on how to Waterproof bathroom floor?

Hi

I am putting a vinyl floor in my bathroom on top of the original floor boards, but in order to raise the floor to the same level as the hall I was planning to board over the wood floor and then lay the vinyl on that.

can you advise on the best board to use, my plumber has suggested WPB or WBP or something like that but not sure what this is?

any help much appreciated

Hey.

WBP (water & boiling proof) is exterior grade plywood. The thickness you require will depend on what level you need to make up between the floor levels.

If you skip on over to the tiling section, I believe there's a sticky that refers to the use of ply on floors.