How old is the house and bath? If you dig down, do you see a lead sheet?
If this is an old bath, you will need to remove the entire base and redo it. This will also mean removing the lower rows of tile on the walls to get enough clearance to put in either a schulter base or a new liner.
Is the plumbing material steel or PVC?
Ron

 

The House is only 5 years old. I do plan on replacing all the tiles in the shower, but not now. I think that all of the plumbing is PVC.
Rod

 

I was only going to remove and replace some grout on my shower floor when I accidently dropped a small tool on the floor. The tile made a hollow sound. I removed the tile, and the thinset came up with the tile. Under the thinset was sand. I've read that deck mud is used, but should it be dry? It is almost like play sand. Is this going to cause a problem in the long run, or should I just reapply thinset and replace the tiles? Any help would be appreciated.
Thanks,
Rod

 

its either a poor mix or not enough Portland. the ratio is 5:1 sand to Portland with just enough water to make it clump together as your mixing it. Thats a bad job by somebody.

good luck with it

 

Just looking at the base tile work would have me believe it needs to be demo'ed as per my first post. Did you find any liner? What's under this bath?
Ron