Ceramic Tile Installation over 2 different substrates
The area that I am going to install the 16"x16" ceramic tile consists of a kitchen with wood subfloor and adjacent room with concrete slab.
I have ripped out the plywood in the kitchen, so only the 2x8 planks remain. As it is now, the wood planks are about 3/4" below the height of the slab in the back room.
My plan, until now, has been to glue and screw 1/2" wonderboard to the planks, then feather out the remaining 1/4" difference between the 2 different floor heigths with floor leveler. Then lay tile directly to the slab and wonderboard with thin set.
After doing some research, it seems that I should be considering an expansion joint between the 2 different subfloors and also install plywood on top of the wood planks, then install the wonderboard on top of that.
Any suggestions are greatly appreciated.