Locating the studs behind a ceramic tile wall as you would find in a bathroom can be a bit troublesome, so we will begin with the simple question, "Why are you looking for the stud in the first place?" For lightweight accessories such as a towel rack or soap dish, it may not be necessary to drill into the stud. A simple screw and anchor system may work and you can drill anywhere for that. You will want to check manufacturer's recommendations for the installation.
If you plan to install something like an assist bar in the shower which is going to routinely support the weight of a human being, you will need to find the stud. A stud finder is usually very useful in finding studs; however, as you add more layers of material it will become less reliable. So in the case of ceramic tiles, you will be trying to sense the stud through the tile, adhesive, and drywall/cement board; this can make it very difficult to locate the stud using a stud finder.
- Your best bet is to start in the very corner of the room. There is almost always a stud there.
- Most studs are placed 16 inches apart so you can measure off every 16 inches and put a little mark on the wall. Use a stud finder around the area you marked to give you a better idea of where the stud might be. You never know, you might get lucky. The reading may be off but it still may give some sort of signal.
- To find the exact position of the stud, take a drill and with a drill bit whose diameter is less than the thickness of the grout, drill a few exploratory holes into the grout. The grout can be easily fixed if needed.
- Insert a toothpick or a thin piece of wire into the hole and see if you can find the stud. Continue drilling little holes in the grout until you find the stud. Most ceramic tile patterns form a nice grid of grout so it is very easy to just go right across the wall about every inch or so drilling exploratory holes. Once you find the stud you can simply close all the other little holes with a little grout and your finger.
One word of advice when drilling holes in any wall, but especially in the bathroom: never push the drill all the way in. Go as deep as you have to in order to get past all the layers of tile and drywall and then stop. You don't want to drill into live electrical wiring or any pipes behind the wall.