Like in the kitchen, we’re using Schluter product called Ditra as an underlayment for the floor tile. Both rooms have radiant floors and Ditra allows the floor to move a bit in the heat without cracking tiles or grout. You could also use concrete backerboard like we did on the walls. Mixing the thin set with the West Philly Tool Library drill:

Before- we filled the dips in the self leveler with thin set first:

Applying the thin set with a trowel:

Ready for the first sheet of Ditra:

All done & ready for tile:

It’s certainly getting bright in here!