Slab opening for tiled shower drain
I removed a broken 4x4 drain tile at the circular drain. Under it, I found something like sand filling the approximately 15" hole through the slab for the drain. It was very damp and even had tree or shrub roots in it. It seems that the drain is actually under the slab and comes up through this hole. Should I remove the other 3 tiles around the drain and fill it with concrete? I'm sure the tile ultimately broke because about 1/3 of it was resting on this sand.
Or was it just a very poor concrete mix that eventually crumbled to resemble sand? I live in Tampa so there really isn't dirt under the slab, just sand.