I am replacing a pre-fab shower with a larger, all ceramic tile shower. I know the flooer must be sloped toward the centre drain before tiling. My question is; what material should be used to make the slope before installing the membrane. Motar or thinset? Please let me know.
Thanks
Randy395

I've just done a couple of those and used mortar. Don't know if that's the "preferred" method, but after years, they're both doing fine.