licensed GC explains: tile over tile 

Exactly what I was looking for. Thank you!

You can also use Eco prim grip and then waterproof membrane on top before thinset.

Perfect explanation. Im sending this video to my customer. Thank you. Id definitely rather rip it out and start over.

Thank you for this explanation! I was wondering about the waterproof membrane under new tile in a shower floor.

Excellent show how and explain how! Thank you!

Why can't you use the primer of "GRIPPER" This stuff adheres to glass & won't come off?

Good information Charlie.

ecoprimgrip is the best as long as your existing floor is secure and solid. Its being used a lot now and I've had no issue with it but doubling up a 2nd layer of tile I wouldnt recommend doing on a plywood floor especially with 16 inch centres. Just sounds risky

Do you have to remove the bottom tile from the shower wall? Is this absolutely necessary?

Why not sand first, then use the tile primer?

Here's to hoping someone answers this question. I'm planning to do tile over tile, but my current surface is not level. What are my options to level the floor before I start applying the adhesion primer, membrane, then start tiling?

How long will something like this last??