Hello! I am a newbie working on an upstairs bathroom re-model and have run into some difficulty with the flooring. The existing floor was vinyl and after pulling up a floor register, I found that there was a 3/4" wood subfloor and 1/4" wood underlayment beneath it. The plan was to pull up the vinyl floor, put down 1/4" hardiebacker, and then tile.
I have since run into two problems. 1) When I removed the toilet, I found what appears to be some water damage around it. The flange was rusted so bad that it sort of flaked away. The underlayment/subfloor may be damaged. 2) The vinyl floor is REALLY hard to get up. I'm only getting a thin layer of it, the bottom layer (a paper-like backing) is still stuck to the floor.
So, I'm trying to figure out how to proceed. Do I need to remove any of the current wood floor or add to it? If I stop trying to remove the vinyl flooring, will the thinset take care of minor differences in height? Can I get a toilet flange around the PVC waste pipe without having a lot of access to the underside of the pipe?
I've attached a picture of the toilet area. Thanks so much for any input.