? For Construction Guys

[niko]

if you get 2" of water again you will still be screwed. the paint will peel off the cement board, the studs (if wood) will be wet and grow moldy. there are a couple of different types of backerboard out there- the grey cement looking stuff seems to absorb more water than the beige colored stuff. tile with a morter designed for wet applications will help with the floor though

[5/0]

I'll agree with Niko,you'll still will be screwed.
The footer should be PT and when you hang the rock make a couple of half inch shims put these on the floor,then rest the rock on it you'll be half inch off the floor and give you a little bit of grace.
Owen Corning puts out this insulation called Mira flex it's soft to the touch and doesn't cause irritation,it's pricey this type might not make a difference if it gets wet,I dunno thou.you might want to ask around.

[Raven]

consider a drop ceiling there temporarily....

with some added light fixtures so it can all be easily removed
and allowed to drip thru into containers on the new tile floor.

ceiling tiles are cheap ...easy to lift and show water stains fast.

Later, when all the drainage problems are solved then
make permanent repairs since MOLD is the biggest health issue.