Ok, in these last 3 pics I started to take up the floor to begin the recess. At both ends I have run into a problem. Neither end landed a on joist. On the bench (pic 3) end I just went ahead and cut back to the joist thinking when I’m ready I’ll just add a pc of flooring to make the base of the bench level. You can see where I cut part out and haven’t cut the rest out yet.
On pics 1 & 2 it is a different story. The overhang is about 51/2”, the wall is there, and on the other side of that is the closet hardie board, and if that wasn’t enough the drain pipe runs about 4” from the floor bottom. What suggestion do you have for securing the floor and shower base? Thank you.