I have installed ceramic tile in my bathroom which has raised the level of the flooring. I understand you can add a flange extender to the exsisting flange to raise the level. This bathroom is on the second level and my question is how reliable are these flange extenders? Will I be able to detect a leak?
Personally, I don't like the extenders. If the flange is now below the new finished floor, then it should be cut out and raised. If it is at least level with the floor, then you might try using two wax rings, one regular and one with a horn. Put the regular wax ring on the flange first then put the one with the horn on top of it. That will allow the horn to center the rings when you press down on the toilet. Be sure the toilet is secure to the tile with no rocking. Use shims if needed. Flush several times to check for leaks. Take some of the grout that was used on the new floor and apply around the base of the toilet.
Flange extenders work fine,if properly installed. I use silicone caulk between the extender and the original (cleaned) flange. The extender must be secured through the original flange to the sub-floor. This is why they have the holes, that will line up with the existing flange holes.
If you have never made a mistake, you haven't done much.