I have an unfinished basement with a concrete floor. I want ot install my own stand in shower and build my own morter shower pan. I have read everything about installing the shower pan liners. My only thought is that it is not a structural floor. It is a floating slab. Am I still OK to build this shower on it or is this a no no because the floor could move, Or am I just over thinking the hole thing??

Is the drainage already roughed in or will you have to open two floors,(see image) to come off the main? And ho were you going to vent your shower?
Back to you, Tom

Over-thinking only a bit, Byron.

You should be fine unless floating slab is cracked or shows other signs of instability.

Tom's questions matter, too. Also -- your project is one of the most difficult DIY tile situations, prone to error even by supposed pro's. Consider using the relatively new shower pan system from Schluter. It helps compensate for skill level and experience, and comes with comprehensive step-by-step instructions (even a video). BE SURE to allow an expansion joint between your shower-tile floor and tile walls, if you use them (strongly recommended).

Done right, you'll have a 50-year floor/shower. Done wrong, and you'll have a potentially hidden disaster.

~Jim Kitchens & Baths by D'Zyne