Putting in a New Bathroom Floor

You are going to have to rip up everything down to the ¾-inch sub floor, starting from scratch. From there, you will need to measure from the sub floor to the top of your toilet flange. That will give you an idea as to where to start. At a bare minimum, you will need to lay ¼-inch backer board on a ¼-inch layer of thin set light mortar and screw it to the sub floor. Talk to a pro at a tile shop for the materials.

The main thing to accomplish is to get the floor leveled. There is an array of leveling products on the market, but again, talk to a pro. Basically, you pour these onto your floor and they level themselves. There are some things that you have to do to ensure that the material does not go helter-skelter all over the place, but it is not a big deal.

Your choice of finished flooring will probably be determined by the remaining "height" that you have to work with. Once again, do not let the toilet flange relative to the height of the floor intimidate you. Toilet seals can easily be "built up" to accommodate any differences between the height of the floor and the toilet.