I've read through hardibacker instructions but I'm still unclear on how to install in my bathroom.
I live in a townhouse and my shower is against one of the firewalls. The firewall, it turns out, is just two pieces of drywall put together with no other spacing between them. I presume, based on when I was tearing out the old tile, that there is a stud. However, I'm not as sure of this since I see no screws or nails on the now exposed firewall.
My initial plan was to screw the hardibacker into the same area where there are existing nail holes. But as I think about how heavy the hardibacker board is, I'm guessing the board will just fall off in a manner of months.
How should I proceed? What was there before was just another piece of drywall.
Here's a picture: https://i.imgur.com/RGNcqTR.jpg