I am prepping a back splash wall for tile I applied one coat of joint compound and before it dried it cracked is the product defective or am I do it wrong.

SOURCE: Tile over a cracked cement floor

You can get a crack membrane to put over the cracks. First use a primer on the floor, this is a primer just for this application, then put membrane on top of primer. these products can be found at home depot or lowes or any tile store.Also do not use cheep thinset. the better thinset is more flexible and will absorb any movement. The cement board would not work as they will move or flex and cause the grout to crack and tile to loosen

tom

SOURCE: one tile in the first row up from the tub fell out

Wetted plaster often dries out like dry sponge cake. When dry try a spray of 25% pva solution. This soaks in and solidifies and stabilizes the plaster.
Whatever you do keep it dry from further water

SOURCE: I'M PAINTING A NEW HOUSE. I PRIMED AND GOT THE

I have been tapeing for 30+ years. You MUST tape over any and all cracks or they will always come back. Sounds like a complete re-do.

SOURCE: Applying tile in a bathroom do you apply the

Just the floor with a notched trowel

SOURCE: wrong floor tile adhesive used

You can choose a kind of super tile adhesive, it can stick all kinds of tiles. Maybe can solve your problem.