Ouch!

I'd cry rather than laugh. And I'd wear a blindfold in addition to the mask.

Seriously, that's a tough situation to be stuck with. Mold remediation isn't too bad, but I've always hated R&Ring water-damaged framing.

Mongo

The only good thing is that all the walls are concrete block, so they aren't falling down. And it's on a slab. I just have to replace furring strips.

Just one comment-- you said they didn't use treated lumber. They're not SUPPOSED to. You'll have wicked problems with warpage and shrinkage using treated lumber.

That tub looks like a shower I pulled apart last november. It's no fun!!

Bill, do they have kiln dried PT lumber a-way a-uppah thar in the northwoods?.

No wacky pretzel movement and it satisfies the need when lumber is in contact with concrete.

They sure do. TCNA emphatically demands that anywhere there's going to be tile, that PT lumber not be used. That's anywhere in the country. For that very reason.

I am glad you said that, because I was thinking of using treated wood everywhere.
They did use treated lumber on the furring strips and some of the base 2x4s. Those were all still solid, although black. I sprayed chlorine on everything and the black is gone. The nails are rusted so I am replacing all the furring strips anyway.
They built a pine wood base under the tub and that was completely rotted. All of the tub support was rotted too. The tub had settled about a half inch, breaking the drain pipe. Which brings up the drain under the lavatory sink... I found it was only slipped together. It was either not glued or it was not pvc cement. Here is how that tub area looks now.

Here is something else I found behind the walls. Florida lizards.

To meet code, we have to use PT lumber where lumber is in contact with a slab on grade. So we'd put down a sole plate made of kiln-dried PT.

The studs and/or cripple studs, top plate, and any other framing besides the sole plate would be whatever non-PT lumber you choose. I usually use douglas fir.

Using non PT in contact with a slab will get a red X from the building inspector.

If they had used PT on the slab under the tub, I think it would have held up a little longer than the untreated pine which lasted about 12 years, along with the other leaky tile work. Pine is what they used instead of a mortar bed. I know you use PT on the slab, but I didn't know it was a shrinkage problem. I would have used it everywhere in the bath. It held up great against the concrete block wall.
I want this next remodel to last at least 20 years and have told that to the contractors quoting my remodel. Do you think that is that too much to ask?
I still see 1950's baths in use in frame houses. It seems a bath in a concrete block house on a slab should last 100 years.

Wow.

Yeah, the PT sole plate will prevent it from rotting from the bottom up.

Proper waterproofing and construction methods will prevent it from rotting from the top down.

Now if we can only figure out something to lizard and squirrel proof the middle!

Mongo