mosaic tiling in a bathroom

[davidmitch]

I am a DIYer tiling a 1st floor bathroom (approx 3.5m x 3.5m). There is a wetroom/shower in one corner. It is a timber floor with 9 inch joists. I have taken up the floorboards and replaced with 18mm ply. But the wife now wants mosaics tiles, which are not compatible with a decoupling membrane, so i think i need to use a backer board. My question is what should I put in the build up, keen to minimise the height of the final floor. Current plan is;
- 18mm ply
- 6mm no more ply
- Electric UFH loose wire
- Self Levelling compound
- Mosaics with flexible adhesive

Thanks in advance for your help with this.