My second floor bathroom is leaking down to the forest floor .

I am going to lift all the time and will redo it

Is there some kind of membrane I can install before laying new tile so the water does not leak through?

I have to replace the drywall now on the first floor and don't want to be doing it again in a year

Any suggestions

Thanks in advance

I would make sure it really is leaking through the floor and not from any drains (most common). Had bathtub cause such issues years ago and changed to shower with well sealed drain. Always best not to use drywall in a flood prone country if any alternative.