Floor tiles on HardieBacker on chipboard - adhesive recommendations?

[Gez]

A few years ago, with advice from the forum, I used Tilemaster Setaflex S1 when I laid my 600x600mm porcelain floor tiles onto 24mm NoMorePly in my bathroom with great results, they are still solid and look perfect.

Now I'm tiling my shower room (first floor on joists), that has 18mm chipboard flooring, using exactly the same 600x600mm 10mm porcelain tiles.

I'm planning to screw the chipboard down well then add the 6mm HardieBacker, rather than the expense of taking the chipboard up to fit 24mm NMP.

Questions I have are:-
- Is this substrate sufficient? The previous 300x300 tiles were laid on the same chipboard plus 6mm ply with no movement at all.
- Do I simply screw the hardiebacker to the chipboard or use a thin layer of adhesive plus screws?
- Is the S1 Setaflex still suitable or are there alternative or better recommendations?

Thanks in advance for your advice.

 

[Gez]

Doh, I watched the HardieBacker video on youtube so am clear on the first two questions that I use a thin layer of adhesive between the chipboard and the HardieBacker boards, and as Setaflex is concrete based this is suitable, and then screw the boards down with 12 screws per board, scrim tape and a thin layer of adhesive to seal the joints.

So, it's really just the last question I need assurance on, that Tilemaster Setaflex S1 is a good adhesive to use for the tiles onto the HardieBacker?

 

[Andrew Owens]

Setaflex S1 would be perfect to use.