Advice needed.......

[mistral]

Have a job to lay travertine onto that green chipboard stuff and want to drop backer boards onto it. normally this wouldn't be a problem but this time it has got underfloor heating beneath it, which will mean the chipboard expanding and contracting rather a lot I imagine. So what would be the best way to fix the backer boards down in this instance? Could I use Sika liquid batten? Maybe Pinkgrip? I'm not so sure polymer modified adhesive would do it.
Oh and to make matters worse, the top layer of the chipboard has come away in places where the previous wooden floor was taken up, as it had been glued down. Have filled the damaged areas with polymer modified SLC.
Replacing the chipboard is not possible as it runs under the walls and kitchen units.
Any suggestions?
Thanks

 

[DHTiling]

Use Hardi 250 and then Dural Ci or Ditra.. only use screws long enough to hold the boards without going through the chipboard.. this is of course deflection is ok.

 

[Dave Ramsden]

I agree or you walk away Had to walk away from a chipboard job a bit ago because the customer wouldn't go with my specification. The tiler he used in the end rang both me and the supplier (who also didnt get the job) to ask what materials to use haha

 

[mistral]

OK thanks, but what else would you use to fix the boards as well as the screws?

 

[DHTiling]

S1 adhesive to take up the voids.

 

[mistral]

Yes, we've got Ultra Proflex SP, which is S1 so that's fine. Only concern about using ditra is the added thickness, customer is adamant that the floor is flush with her existing one. Any idea of combined thickness of hardi and ditra ( or Genesis G as it's cheaper).
And thanks for taking the time to answer.

 

[DHTiling]

6mm hardi 250 and 3 mm Dural CI..( new version).. IMO do not use old version of the Dural Ci or equivalent..

 

[kiwi Mark]

Agree do not use old version Dural or Genisis . I guess this answers my thread ( Myson underfloor ) where I got no response ?

 

[mistral]

What is the difference between new and old versions?

 

[Stewart]

There are a few problems with the old one, so just make sure you get the newly designed one, no matter how good the offer is....

 

[kiwi Mark]

Dont get how the others are still able to sell theres Dural have been very helpful at soughting my probs out.