18mm ply & Hardiebacker floor?

[scowps]

Hi guys, I'm an 'enthusiastic amateur' ! and have read this forum with interest!

I'm renovating our bathroom and have various problems. The floorboards have been taken up as were knackered and a bit woodwormed, joists to be treated before replacing - with, I hope, 18mm ply and 6mm Hardibacker - is this adequate if I noggin the joists. I didn't really want to go to 25mm ply due to the 'step'.

Problem 2: One internal wall is plastered brickwork and covered in paint and looks a bit tired - problem is I can't overboard or hack off and board this wall as I only have the thickness of the door frame to get my limestone in! My only thought was to get the wall replastered and then tile on that - what finish should I go for - a full skim or just browning or tile straight onto the bricks after some sort of coating? Max thickness from brickface to door hinge is 30mm, and the limestone is 10mm!

Any advice much appreciated

Scowps

 

[lancenotalot]

If you are replacing with ply then you won't need backers,you can tile direct onto the ply.

Sand the paint off then prime with acrylic primer,you can then tile onto it.