Have you tried to see how solid the existing cast iron flange is?
It may be that it is very solid, and if so, slap a wax ring on it and drop a bowl down.
The gray "tin", is a lead poured joint.
I'm trying to replace bathroom floor tile and toilet. after old toilet removed. I found the flange is not level. the front side is higher than back (wall) side about 1/4". The problem is the flange is cast iron and soldered by tin on the metal pipe. Hard to replace and no any screw/hole on top (only two notches for toilet holding screws). the flange is not touch the concrete floor only holding by 4" metal pipe under.
a. Do not change anything, the flange was designed that way (?). just clean and put a new wax ring on it to install the new toilet.
b. use construction epoxy resin to fill the gap between the flange and floor to add extra support. let wax ring to handle the 1/4" uneven level gap
c. use a steel flange repair ring has extra screw holes outside of the flange area (because the old flange has no screw hole on it, so the standard screw holes on any extender/rings cannot go through). screw and force the front of the flange going down 1/4". Make it back to level evenly. (will this way broken the pipe?)
d. use something like Fernco wax free seal. don't touch the old flange.
Thanks for prompt help.
I google a picture that show the same model of flange as the one in my house.
The flange is remains 85~90% good after all rust removed. Since the flange is soldered on the pipe, it will not move around with normal touch. But the concrete foundation has 1/4" to 1/2" gap around the metal pipe. It will move a little be (flange and pipe move together) if I force it.
The bottom of flange is now above the concrete floor surface 1/4". After new tile installed. the top of the flange will be 1/8" above new tile floor.(but the back side will be a little lower than front side, about same as new tile floor surface.) I got a "Push-Tite™ Gasketed Closet Flange" from local hardware store. Should I use it to extend 1/4" high and it will also cover the inner of the old flange? (the old cast iron flange was surround at outer of the 4" metal pipe.)
Another thing worry me is the wax-less seal ring is really better than traditional waxring in my case? is there any side effect if use wax-less seal ring? (I also bought this: )
Last edited by mrcleaner; 11-02-2012 at 04:15 PM.