How should I fix a previous owners mistakes in this bathroom? (see pictures)

Question

I recently bought a fairly old house (circa 1900). I am in the middle of demo-ing the full bathroom and need some help. After removing the fiberglass shower wall, I found standard drywall which was, of course, moldy. That drywall was nailed on top of wood paneling. The kicker is that the walls for the front and back of the shower were built right up against the drywall/wood paneling on the back wall.

The walls at the front and back of the shower are supporting drywall for a closet on one side and the kitchen on the other. I am not renovating either of those rooms so would like to minimize damage to them. What would be the best way to get rid of the mold and get this area ready for the new tub?

Answer 1

I don't see the mold you're talking about, but my go-to is straight industrial bleach, available at most home centers and hardware stores. I apply it generously (read - dripping wet soaked) with a spray bottle. Give it a couple hours, spray it again.

Repeat until all mold is visually gone.

Get rid of that insulation too. Might be harboring some of the mold spores.

...and, of course, only do it in well-ventilated area, blahblahblah, and so forth....

Answer 2

I am not a handyman, but if the structure looks solid, I would not try and patch the job. I would bring it down to the studs and then put in durock/hardy board/some water friendly board.

The walls may be uneven since it was done a long time ago 1900, and the uneven walls could cause you more headache so I would look into that.

Now when you take the walls down, and rebuild that may bring about need for new fixtures, which means possible plumbing to take into account.

I would get estimates from plumbers, and certified tile guys so you go in knowing what you are getting into.