Q: I have come into a problem with the floor under my toilet. When I took it up to replace it with a new toilet, I found that the hole under the toilet was the same size as the toilet itself, instead of the round hole just for the flange. How can I put a new floor down and what supplies are needed to do a proper job? How do I bolt the flange to the floor, since right now it's just sitting out there and not attached to anything? Will the floor come up easily or will I have to cut it off? How many people will it take to do the job? Once the floor is down, do I have to get it tiled before I can put the toilet back in place?
A: You are going to have to rip up everything down to the 0.75-inch subfloor, starting from scratch. From there, you will need to measure from the subfloor 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 0.25-inch backer board on a 0.25-inch layer of thinset light mortar and screw it to the subfloor. Talk to a professional 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.