subsurface for tiles half bath (shower)

I hate drywall in he shower. You should always use cement board or Hardibacker.

Use Hardibacker, or equivalent. Sheetrock is not intended to be used in wet locations. Sheetrock is a little cheaper, sure, but do you want to do this job again? I don't find Hardibacker that much more difficult than sheetrock, just be a little more careful with the dust. Cutting it outside is good. ;-)

Uno wrote the following:

Green board (a waterproof gypsum board made for bathrooms). It doesn't matter what the outside humidity is, the shower, and sink make their own own humidity.

Thanks all for comments. Looks like we have a split decision. If you were going with either hardibacker or cement board, which one would you go with?

The tile might end at eye level. Would you only put hardibacker/cement board behind the tile and have the exposed part as treated drywall anyways?

Does using drywall present a problem with laying tile itself? (For example, not adhering and having them fall off a vertical surface)

I happened to have something that measured temp and relative humidity in my steamy shower this morning. It gets up to 40% but returns to 20 within the hour.

I've done both. Hardibacker, hands down! It's *much* easier to work with. I don't find it much harder than sheetrock. I had problems with the edges of the cement board crumbling and it's a real PITA to cut right.

I'd put Hardibacker behind tile in the livingroom. ;-)

If there is no chance of it getting wet, sure. When I did my laundry I put the Hardibacker up to a line just below where the tile stopped, then continued up with sheetrock. The tile stopped above all the plumbing so there was little chance of water damage. Sheetrock is easy to replace anyway. Unless, of course, there is tile on it. ;-)