I have been doing a lot of reading and it seems there is a lot of information out there that has sorta confused me, so I thought I would ask you guys and hopefully you can give me what I need to know. I am going to be tiling a small bathroom that has sheetrock. (FIRST TIMER DIY’R) It will not be around the back of a shower/tub as its fully enclosed. But the wall that joins it I will be tiling with a tile that has glass and rock in it. It will only go 42 inches up the wall and will also go above the vanity. Do I have to replace my sheetrock with backerboard and if so, what if I cant cut it all out as some I cant hit my studs as the placements are not reachable. Would it be ok to leave some sheetrock? I think its my understanding the reason to replace the sheetrock is because of moisture. Is there something I can use that can seal the sheetrock? I cant place the backerboard over my sheetrock either because of my counter top backsplash isnt wide enough and it would hang over it and because of the wall that joins my shower is framed out and would stick out over the frame. This question I guess goes along with my kitchen project too. I just hate having to cut out my sheetrock and replace it if I dont have to BUT I dont want my tile to be falling down or mold and mildew behind my tile. Thanks so much for the advice.
Here are a few things to keep in mind:
If the tile isn't going to be hit by shower spray, or be otherwise soaked with water, you don't need backerboard behind it.
For what you're planning, you could install the tile right on the drywall. Just make sure the paint is well adhered, and clean the paint very well; scrub it with a TSP solution, rinse well and let it dry thoroughly. For that kind of application, I'd mount the tile with mastic instead of thinset, and I'd let it dry thoroughly (about a week) before grouting.
One word of caution, though. Sometimes builders used greenboard in bathrooms next to showers and sinks. Greenboard is a kind of water-resistant drywall but it's *not* a good substrate for tile because it's softer and more flexible than regular drywall. So, you might want to do a little bit of exploratory surgery before you begin your project. Use a utility knife to remove a little 1/2" square section of paint & paper from the face of the drywall. Peel back the paper and look at it carefully. If the paper is green, it's greenboard and you shouldn't tile over it. If it's just white or grey, tile away to your heart's content.