I am doing a bathroom remodel down to the studs. The wall behind the sink will be tiled with stacked splitface marble. My questiom: what goes on the wall before the tile? do I drywall, then add the hardiebacker on top, or just attach hardiebacker? I ask because then I have to know exactly where the drywall would end and hardiebacker would start, which is dependent on cabinets and counter top etc. Or, I just drywall everything and add hardiebacker once exact perimeter of tile is known. Or is hardiebacker even needed. Could tile go on drywall?
HardieBacker on the studs, no drywall. In this zone the tile will hold better and last longer. Outside the damp or wet area, I change to green or blue board - a water-resistant type of sheetrock that I use in bathrooms. I will use HardieBacker for the width of the sink to the next stud, or in a tub / shower area, then green or blue water resistant sheetrock.
I have seen water-resistant sheetrock hold up for 30 years and even regular sheetrock for 20 or close with well-sealed tile. I have never had a quality cement board fail or need repair so this is the best in my opinion.