Never know what you’ll find when you tear into someone else’s work. When I demoed my second bathroom, I discovered that the wall tiles around the tub/shower were attached directly to drywall. No cement board or any kind of moisture barrier. Luckily, the drywall wasn’t destroyed, although the bottom row of tiles were loose in a couple spots. When I remodeled my first bathroom, I found a surprise pocket door frame behind the drywall. Since the wall was already framed for a pocket door, I installed a new one.