Should Ditra matting be used for this job

[Kevboy]

I have a wet room floor to tile upstairs in a house. The builder is fixing hardibacker board followed by underfloor heating and then self levelling before I lay marble tiles. I told him I think Ditra matting should be used as well, due to marble tiles. Thoughts please and would Ditra matting be laid on board and then heating or heating under Ditra.

 

[WetSaw]

Use Ditra Heat on top of the backer then tile, no need to latex.

 

[Flintstone]

Your best bet here would be to use ditra heat.
But failing that I would do as you say above then after the self levelling, fit a thin anti fracture mat such as bal rapid mat or tilemaster. Also, concicder using insulation boards instead of hardie

 

[Matt Bott]

I'd defiantly use anti fracture mat as above ditra heat would be your best bet, other brands are available

 

[Kevboy]

Doesn't the ditra heat do the same as the anti fracture mat, is it overkill?

 

[pjohn]

Has it been tanked, seeing as it's a wet room?

 

[Old Mod]

Doesn't the ditra heat do the same as the anti fracture mat, is it overkill?

The purpose of the Ditra heat is that it's your
3-4 layers all in one.
Your decoupler and your ufh, and as Schluter don't advocate latexing over it, that element is done away with.
If you tape the joints with Kerdi Keba band and Kerdi Coll, then it's also a waterproof membrane.
One stop shop.