Does hardibacker need adhesive on caberdek?

[wasabi]

Hi folks

Tiling a bathroom in a new build. Floor is caberdek, solid and flat. Could I just screw the hardi boards down? There's zero movement, or should I still use the adhesive bed? This caberdek looks a bit waxy or has a coating. Cheers

 

[wasabi]

fyi I called Hardibacker and they said to use the adhesive still. Not sure what it will do as it won't stick well to the waxy chipboard and the floor was flat and solid already, but heyho

 

[Slippery]

Hi Wasabi,
I saw your post this morning but didn't really know the answer.
I thought about it this afternoon and was going to suggest using adhesive anyway, as it will bond the substate and it gives an extra layer of protection, in my opinion, you can't go wrong by making sure there is nothing that will come back to bite you on floors.

 

[Hobnob]

Even on caberdek I would always prime and then apply adhesive first. It will fill even minor undulations between hardi and chipboard and with the screw fixings will ensure a solid substrate to tile to.