I am redoing the floor in a bathroom. This bathroom was expanded into an addition on the back of our house. When I pulled up the old tile, I exposed the original brick house wall sunk at a depth of 3/4" between the plywood subfloors - see attached floor.jpg image. The original builder had just put some loose wooden spacers on top of it. I want to fill this gap with something more permanent and level the subfloors between the two sections of the bathroom before I lay new ceramic tile.
I am thinking of cutting a strip of 3/4" plywood and securing it to the bricks with my power hammer to fill the gap.
Next I thought I would use SLC across the entire floor to level it.
Then finish with sheets of Wonderboard or Durrock on top of the SLC before I lay my tiles.