Hi, About three years ago I had a "tile guy" rip out my builder quality ugly 2 inch white tile shower floor and replace it with a river stone (mocha grout) shower floor. The area is approximately 20 sqft. I really do not know his experience with shower floors. He did it for me as a little extra job when I hired him to put in a flagstone patio in my backyard. I have layed tile in the kitchen and bathroom before and with my little knowledge he seemed to do everything right. Three years later I am having numerous problems. 1. I should have never chosen Mocha colored grout for a shower floor. It is very hard to clean and over all a nightmare. 2. There appears to be a corner in the back that is not draining properly and if we left town for the weekend and the shower was not used the grout still looked a bit wet back there. 3. I do not know eactly what he used as the sealant around the floor perimeter but I do not think it was properly sealed along the wall grout lines. 4. About six months ago those beautiful little flies that are heart shaped appeared to have moved in. Though I usually try to use earth friendly pest control, I have now tried everything to get rid of the sewer moths. They seem to be resistant to anything and everything and have taken permanent residence somewhere within my shower.
A few notes...I am sure that he did acid wash and seal the river rocks and grout. I have not sealed it since he did (so maybe all of this is my fault). My shower walls are made of the manufactured marble. They look nice and I have debated on ripping it out and tile the walls, but it is very easy to clean and control mold and soap scum.
Now to my problem... About a week ago I decided that I was going to take out all of the caulk and recaulk the entire shower thinking the moths were coming in from old caulk lines. I was also going to acid wash the floor and reseal it. I took out all of the caulk and somewhere in that process I decided to rip up the floor as well. When I started to rip up the floor in the back left corner (the area that never seems to dry) the dry pack or subfloor started crumbling. I now have about a half of a square foot that has been pulled out all the way to the drain pan.
I dont know what to do. I am letting it sit so that it can dry out. It has now been almost three days and the floor is patchy with some dry areas but it is still wet. The moths are going crazy. I have seen more in the past two days than I have ever seen. I think it is because they no longer have a moist area that is dark and undisturbed. I am trying to get an exterminator out so he can spray up the drain pan behind the fake marble wall (which is where I think they are hiding out).
As far as the floor.... do you agree with letting it "air out" or does it matter? Why did it get so wet like that to begin with? Is that normal to have moisture that can never escape the "dry pack" area? If it is normal is it okay for me to put mortar down and start laying my tiles even though it has not fully dried out?
I guess my biggest question is... Do I now need to rip out the entire dry pack floor and put down a new one or can I just fill in the area that was dug out to the drain pan and make sure is it slightly more elevated than before to allow proper drainage in the future.
I hope I didnt type too much. I was so excited to find your forum. I appreciate any help you can give me

Kelli