Chipboard and levelling?

[HiDIYGuy]

Hi all,

I have a small WC about 2m2.

I realise now, that I should have taken up the Chipboard floor, levelled the joist and replaced with Ply. However, I went ahead and fitted and levelled the concealed toilet and have burned too much time to rip it all out.
I realised, that the floor was not entirely flat, with about a 10mm drop-off in one corner.
I have 6mm hardie-backer, which I was going to lay down over the ChipBoard and then tile over that.

What's the best option now for levelling before tiling, without removing the chipboard? Is it to Prime the floor, lay the hardiebacker, then self-levelling and tile, or, Prime, self-level, Hardie and then tile?
Or neither of the above.

Many thanks in advance!

HiDIYGuy

 

[Dave]

Lay the hardibacker and make sure all edges are sealed to prevent leveller seeping away and self level. Use a levelling compound suitable for timber floors and depth required

 

[Andrew Owens]

Hardibacker then leveling compound.

 

[HiDIYGuy]

Amazing, thank you both for the replies. I shall take your advice.
One thing that slightly puzzles me, is if both the Adhesive used for Hardie and the tile are both water based, is the risk of swelling the chipboard the same? and is the order you suggest. more about getting a good surface for tiling onto?

 

[Dave]

Amazing, thank you both for the replies. I shall take your advice.
One thing that slightly puzzles me, is if both the Adhesive used for Hardie and the tile are both water based, is the risk of swelling the chipboard the same? and is the order you suggest. more about getting a good surface for tiling onto?

The water used in the adhesive mix won’t effect the chipboard , it take quite a wetting for it to swell. And yes it creates a better surface to tile too on humidity and expansion issues.

 

[HiDIYGuy]

The water used in the adhesive mix won’t effect the chipboard , it take quite a wetting for it to swell. And yes it creates a better surface to tile too on humidity and expansion issues.

Thanks Dave, much appreciated!