I hav replaced my old floor in my bathroom and have installed ceramic tile with a cement backerboard. The old flange had some play in it, so i was able to lift it and install it on top of the cement backboard. But now with the ceramic tile installed the flange now sits only about 1/8" about the surface of the new tile. My question is, do i need to install a flange extension or is the 1/8" enough to install the toilet normally without an extenstion?