Designing Kitchens and Bathrooms - Mold behind shower tile

I found mold behind the tile just above the tub. I also noticed that they did not use cement backer board - regular sheetrock. Beyond the first two bottom rows of tiles, the rest seem solid. Am I going to have to remove all remaining tile walls and replace with cement BB? My greatest fear is the mold.

Yep, you should demo it all. Tiling directly to drywall or greenboard in a shower is a disaster waiting to happen.

We'll walk you through reconstruction, so don't worry about that, eh?

I had the same problem and I cut out the tile area that gets the most water, replaced with cement board, and retiled. Ideally you should demo it all, but the tile I had used was expensive so I cut corners. When you cut out the area near the mold you should get a good idea of how bad the problem really is.

Well, we tore out the tile on the long wall (parallel to the tub) and as we got higher, the mold got less - very little at the top. We did see something odd though. Our house is a concrete block construction and the tub is on the exterior wall. Then you have the furring strips. Now the interesting notes:

1) No vapor barrier.
2) Thin strip of what appears to be standard wall insulation between the furring strips.
3) Sheet of drywall, then a sheet of greenboard over that. The drywall had mold on it.

We live in central FL.

I would replace the std insulation with some rigid foam board (blueboard), fur out the space with some plywood strips to match the old drywall then install 1/2" hardiback...should be good to go from there.

central florida...vapor barrier outside side of insulation

I would replace the std insulation with some rigid foam board (blueboard), fur out the space with some plywood strips to match the old drywall then install 1/2" hardiback...should be good to go from there.

central florida...vapor barrier outside side of insulation

Thanks! I did some research and it seems the best thing in these case WOULD HAVE been to seal the concrete. But since I don't have access without tearing out the remainder of the wall, I plan to do the following:

1) Rigid foam board between furring strips. Seal the cracks with expanding foam.
2) Put in a sheet of cement BB over that.
3) Install new tile or 3 pc surround.