Many reasons why I never recommend installing tile over tile. Not all adhesives can bond tile to tile. You want a firm grip on the back of your tiles to make sure there’s no lifting or breakage once they’re installed. Already laid tiles don’t provide the best surface for new tiles to grip. | Mike Holmes

Tile Chick Quick Tip: Tiling over drywall. Yes it can be done! - I often see hate about tiling over drywall. If your substrate is solid throw a tile bonding primer on and send it! (Within reason) Drywall that is not structurally sound, has paint or texture that is peeling or damaged should be removed and replaced. If it’s fresh and clean I’ll go over it! - Would love to hear my fellow tile friends thoughts on this topic and for my diy/real estate/homeowner friends this is something that can work