newly poured shower pan deflection

[Denvergsd]

I recently poured a 1" "top mud" for my shower pan. Today while standing on the pan in the corner I heard a sound. Not a cracking or a creaking but just a sound as if some dirt had been shuffled across on the floor. Upon inspection I noticed that my pan, or as far as I can tell, my top mud layer has some deflection in it. The is apparent almost all the way around my pan except on the curb side.

I don't understand how this could have happened as I packed the heck out of it when putting it down. My only guess is that my pan liner must have not been seated in the corner enough where it transitions from my preslope (horizontal) to my studs (vertical). I didn't notice the deflection when just my preslople was down.

Below is a video showing just how much it deflects. In the video I'm pushing down with approximately 60 pounds of force with my hands about 12" away from the corner. One thing I don't understand is that if there is truly a problem then why does the whole corner not simply break off when I (a ~200 pound guy) stands directly in the corner?

Thanks for the help.

 

[Jadnashua]

When you say 'pour', what exactly did you use for the setting bed? Typically, that's deck mud, and it is more like wet beach sand that needs to be packed and placed verses being poured. The setting bed needs to be porous to allow the moisture that will get there to percolate to the weep holes of the drain. Most anything you pour would not allow that.

If the whole piece can move up and down as a unit, it probably wouldn't crack, but it would be problematic for tile and the joint between the floor and wall (should be caulked or an engineered joint, not grouted and thus not brittle).

 

[Sponsor]

 

[Denvergsd]

When you say 'pour', what exactly did you use for the setting bed?

"pour" was entirely the wrong word. I used quikrete's 60lb sand topping mix and added ~30lb of sand to it.

 

[Jadnashua]

I'd as your question over at www.johnbridge.com where they specialize in all things tiled with lots of pros.