How do you handle bathtubs/showers in rehab projects?

[Patrick Philip]

I went to Home Depot to look at prices for showers and tubs. They sell everything as a separate piece. The bathtub is one piece, and each shower wall is a separate piece for a total of 4 pieces. I didn't see any "top pieces" for sale.

Looking at the bathrooms in my house, it is different. The bathtubs/shower pans are one piece with the walls, then there is another piece on top, for a total of 2 pieces.

Did they change how they made these? I think Home Depot sells one-piece sets on their website, but from what I hear these are harder to install.

If I remove a shower/tub set like I have now (my home was built in the 1970's), then it is possible that there is no wall behind the back shower wall and no ceiling above where the old shower ceiling was.

Putting in some drywall behind the back wall should be easy enough (for a contractor to do), and perhaps the same for the ceiling, but what type of material do I use on the new ceiling? Is it just drywall? Do I have to make it waterproof in some way? Does it have to be tiled?