Just found out the washroom floor and flange are uneven.:( The floor end far from the door is 1 5/8 '' higher.I am thinking of using concrete to even out the floor, then what should I do with the flange? It is uneven and will be much lower than the floor after I apply the concrete and lay the tiles.:confused:

If the flange is OK then you can use flange extenders,(see image) to bring the flange up to grade after the floor's leveled. Good luck, Tom

Thanks Tom, is the uneven flange going to cause any problem after the floor is leveled? Will the flange extender extend 1 1/4'' to the new floor after the tiles are laid? Sorry for so many questions, first time washroom DIYer, Sam.