I used two wax seals to set my toilet since the flange is 1/4" below the new tile. At first it seemed to be water tight but after a few flushes I noticed water seeping and pulled it out. As can be seen in the photo, the wax ring slid off center. I couldn't use just one ring since it protrudes about 1/4" below the toilet so that would just barely touch the flange. I found the flange extender in another post and will try that. One of these
So to my question. Is this the correct approach? Should the flange be level with the floor prior to installation?
Edit: The correct height of the flange is sitting on top of the finished floor. Of course with a remodel this is almost never going to be the case after tiling. There seem to be various methods to raise the flange. Many say the double wax ring is problematic since it can collapse into the drain over time. This link discusses a number of products to solve the problem. In summary, the set-rite (~18 + shipping) is the most expensive and apparently the only code approved product. The cheapest option is flange extenders ~$3-5. The funny thing is neither the tiler or the plumber that worked on my bathroom mentioned anything about the height problem, which leads me to believe the common solution is the double wax ring.
Best Answer
The flange should sit on top of the finished floor, if it doesn't you'll have to modify the plumbing or find another way to achieve this.
Notice in this image how the toilet waste pipe sits just inside the flange opening, this is the proper way for a toilet to sit on a flange. Even without a wax ring, this union is not likely to leak under normal circumstances (I'm not recommending a wax ring not be used).
Wax as a waste pipe?
Some folks recommend using a thicker wax ring, or even doubling up wax rings. The problem with this, is that you end up with a waste pipe made from wax. Now this might hold up, but more than likely it's eventually going to fail, and leak.
Modify the plumbing
If you have access to the flange from below, you might be able to modify the plumbing to make the flange sit atop the floor. In most cases, however, this is not an option.
Adapters
There are adapters available, that solve this exact problem. The Set-Rite Toilet Flange Extender Kit; described in the answers to this question, Comes with different size spacers, which allows it to compensate for various sized offsets.