Repairing Cast Iron Toilet Flange?

I just removed my old toilet. What I found was a thin flat metal toilet flange bolted onto the original cast iron flange. I removed this and am hesitant about putting it back because it doesn't seem like the most leak proof method. The original cast iron flange is corroded and pieces around the edge have deteriorated away. Also, some of the metal in the center is very brittle and I could just chip it away.

I am removing any loose metal and cleaning it as much as possible. My thought is to get a PVC flange that fits inside of the cast iron pipe and bolt and seal this onto the original flange (original flange is flush with the tile floor so this would give me the proper height). Is this a good idea? What would be the best product to seal it with (I was thinking of using plumbers goop)? Thanks for the help.

mstruttum,

You're definitely better off going with the PVC !

I've done a bunch of those old Cast Irons, and they're more trouble than their worth. CHANGE IT OUT!!!

On the seal. you're only dealing with Gravity Flow, so you're not going to have it rated very high. Some of those new PVC Flanges come with their own sealing Ring, but, you can use Silicone, Plumbers Putty or the Goop. Just remember if you do it with anything that hardens firmly, IF you're off on your height, it will be hard to re-do.

Have a good Day !
S.W.

A new PVC shouldn't exactly fit inside the old cast iron pipe?

What I have done is cut off the old one, put a new PVC one on (make certain the floor is completely level and stable where the flange is, the new PVC break really easy if the floor isn't level and the flange can move)

You'll have to cut off about a foot of pipe below the floor so you can put new 6" or so PVC pipe into the new flange and the use a proper rubber adapter to adapt from the PVC to the cast iron.