Three Tiles Kept Falling Off My Tub Wall Until I Looked Behind Them

The first time a tile fell off my shower wall, I figured the adhesive had just failed. It happens, right?

I cleaned the back, smeared on fresh mastic from a tube I had under the sink, pressed it back into place, and called it done. Ten minutes, problem solved.

Two months later, the same tile was on the floor of the tub again. This time it brought a friend.

I did the same thing—new adhesive, firm pressure, overnight cure. I even added a little extra around the edges for good measure. That should have been the end of it.

But four months after that, all three tiles let go at once. They slid down the wall on a Sunday morning while I was brushing my teeth, leaving behind three pale squares of drywall that looked wrong the moment I saw them.

That’s when I stopped reaching for the tube of mastic.

I pulled out my utility knife and gently pried at the edge of the exposed area, just to see what I was really dealing with. The drywall came away soft in my hand, almost like damp cardboard. There was a faint musty smell, and along one edge I could see a dark stain starting to spread.

The adhesive had never been the problem.