Hi, I have a 4″ cast iron closet flange that is sitting about 1″ too low due to a bathroom remodel. The flange is joined to the closet elbow with a lead and oakum joint. The flange is in good shape. Is there a product available that would let me build up the flange to the correct height? I am thinking of something like stackable annular rings. I would rather not have to remove the flange. The flange and elbow are not accessible from below in case something breaks. If I have to, how difficult is it to melt the lead and pull the flange? I would then have to use a deeper flange that would sit higher. Are these available? Thanks for your help.