Cast Iron Toilet Flange - repair or replace

[JoeTheStack]

I have a cast iron toilet flange that is broken off where the toilet bolts go, as shown in the pic below. I was going to use a pair of those flange repair brackets, but I am concerned there is not enough flange left to make a good seal when the toilet is installed, so I think it would be best to replace the flange. Should I remove the flange from the pipe, and install a new ABS flange that inserts into the old iron pipe with a rubber seal? Or should I cut off the iron pipe just below the flange fitting? Backerboard is to go on top of the plywood, then tile. It would be nice to remove the toilet flange, finish the floor, then insert the repair flange, screw it down to the floor, then tighten its seal expansion bolts, and voila - done. But what if the inside of the iron pipe is rough, pitted, etc, and the replacement flange doesn't make a very good seal to it?

 

[frodo]

I would, unscrew the sub floor, and cut the cast below the floor.
use a proflex cast iron x pvc shielded band. stub up with pvc

then replace the floor, install the backer board and tile, then the new flange, screw it to the floor

the cast looks to be 4''. i would stub up 4'' pvc
and use a http://www.supplyhouse.com/Sioux-Chief-883-PT-Total-Knockout-Closet-Flange-w-Plastic-Ring-3-Hub-4-Inside?gclid=CjwKEAjwkJfABRDnhbPlx6WI4ncSJADMQqxdvGxhm6BNv6PJHT5kTFVNoF-ZcBA58gP8KwkTaQ3kdhoC5EHw_wcB

 

[JoeTheStack]

Thanks for your reply. If I understand it, your suggestion is to cut off the cast iron below the floor, then use the coupler you mentioned to stub up a 4" PVC pipe. Then go ahead and finish the floor, then install a PVC flange in the traditional PVC manner (glue) and fasten it to the floor. This would eliminate the use of the flange repair part that inserts into the cast pipe, and also avoids removing the cast flange from the cast pipe. I will check on the length of the vertical section, but presumably there is room for the coupler and the flange. This seems like a better approach than what I described in the first post.

It seems like they're moving away from ABS in favor of PVC for DWV pipe, though they still carry both at the retailers. I wonder why.

Thanks again for your time and advice. I will post an update on how it turns out.

 

[frodo]

Thanks for your reply. If I understand it, your suggestion is to cut off the cast iron below the floor, then use the coupler you mentioned to stub up a 4" PVC pipe. Then go ahead and finish the floor, then install a PVC flange in the traditional PVC manner (glue) and fasten it to the floor. This would eliminate the use of the flange repair part that inserts into the cast pipe, and also avoids removing the cast flange from the cast pipe. I will check on the length of the vertical section, but presumably there is room for the coupler and the flange. This seems like a better approach than what I described in the first post.

It seems like they're moving away from ABS in favor of PVC for DWV pipe, though they still carry both at the retailers. I wonder why.

Thanks again for your time and advice. I will post an update on how it turns out.

yes, take note, the flange i linked you, fits inside the 4'' pipe, so you can
set the flange on the backer board, tile up to it

that is assuming you are using thin set and 3/8'' tile [1/2'' total]

that way, it is easier to screw down, you do not have to drill the tile

 

[MasterPipe]

Thank you so much for sharing this information, it's been a really interesting read, Thanks for the great tips.

 

[3DPlumbingProducts]

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