I have removed our old 1930's toilet and discovered that the flooring and the 4" cast iron pipe are connected by a lead sheet collar. I am thinking to install an Oatey twist and set flange and bolt it to the flooring. Is this right? How can I ensure a good seal to the pipe which does not have a smooth surface? What is best: cast iron flange, abs flange, ss covered flange?
Any other ideas? I am reluctant to remove the lead and start over.