The lowest profile waterproofing and tile underlayment in one is the wedi Subliner Dry Sheet membrane. It is applied over a suitable structural subfloor using modified thinset ( trowel size ¼” x ¼” square. This membrane would overlap onto the Fundo Ligno by 4”.
4 inch strips of this Subliner Dry membrane, or wedi Subliner Dry Sealing Tape , are installed as a flashing reaching 2” up the wall and 2 inches down on to the Subliner Dry membrane. The membrane will do the waterproofing and it can be tiled over right away ( Robinson Floor Test rating: “Heavy (duty use)” ).
But even though you can always recess Fundo Ligno for its entire ¾” thickness, in some cases you may want to recess less deep. Such as when cement board or other underlayments are installed over the bathroom floor. Accordingly, you would increase the Ligno in its recess by the thickness of such underlayment plus the thickness of a waterproofing layer like Subliner Dry ( to be installed over cement board, floor leveler screed, or other non- waterproof surfaces such as uncoupling plastic membranes).
As you can see, it is always possible to increase the height of Ligno in a recess. This can be done easily by installing a wedi panel or cement board with the needed thickness below Ligno.