New shower pan / gut?

[JLD1983]

hi all - we discovered a leak in our shower stall. It left some staining on the ceiling below. Shower stall done about 15 years ago. After some investigation, it was determined it was likely the shower pan. Our tile guy just ripped open most of the first row of wall tiles and the shower stall curb. Behind the tiles is dry wall! That’s it. No waterproofing or cement board. Dry wall practically crumbled on touch. Also, insulation in the walls. We haven’t used the shower in 3-4 weeks and there is still some moisture. In the meantime, we ordered a custom size tile redi shower pan. The original Plan was to install that with tile over it - only removing the floor, curb, and first row of tiles. However, due to the recent discovery, looking for advice. Do we take down all of the tiles in the entire shower stall and gut down to studs? Can we get away with just the first row or two of wall tiles? Should we assume nothing is waterproofed in entire shower stall wall and gut/redo? What about the floor tiles right outside the shower stall? Some photos below.
Oh, also, bleach was sprayed/poured for now. Was concerned about mold.

 

[Jadnashua]

FWIW, in most showers today, the walls aren't really waterproof, but are resistant to damage if they get wet. Neither tile nor grout is considered the waterproofing on a shower...they are the decorative wear layer. Conventional shower construction calls for a moisture barrier behind the walls and a cement board on the walls, with that moisture barrier lapped into the shower pan. Drywall, even moisture resistant stuff, hasn't been approved for use in a shower for decades.

THere are numerous topically applied waterproofing methods/materials you can put on the walls to make them actually waterproof verses just water resistant. Most of the big manufacturers that sell thinset also make those products. Laticrete, Mapei, Custom Building Products, etc., all make a paint on waterproofing. Some of them also make a waterproof sheet membrane to include Schluter.

THere are also a few companies that make tileable, waterproof, coated foam panels designed for waterproofing then tiling shower walls. KerdiBoard, WediBoard, are two of them. THose just get screwed to the joists, the seams and screwheads waterproofed, and you're ready to tile. Easy to cut, carry, and totally waterproof if done per the instructions.

Personally, I'd gut the shower and rebuild it to industry standards. If the shower valve does not have anti-scald tech, replace that in the process.

WHen it comes to tiling, my goto place is www.johnbridge.com. Lots more pros that specialize in tiling there. Plumbing questions, and other related subjects, this site is great.