Norm Dion wrote:
Yes, I definitely intend to drill into a stud. But my original question was
what can
I expect to encounter on the way to those studs, and how thick.
It's important in helping me locate the studs behind the tiled surface.

Sorry. I misread your post. You wrote exactly what you meant and that
can be confusing.

If your house is relatively new, say within the last thirty or forty
years, the odds are great that there's a half inch substrate with the
tile on top of that. Figure 3/4" - 7/8" for that scenario. If your
home is older than that, it might be a bit thicker. Figure 1" - 1.5".

How do you intend to locate the studs?

R