I have a 4" stub, which I believe to be Iron (how can I verify?), for a toilet in the soon to be bathroom in my basement. The pipe is 14" off the wall, so I was going to use a brass offset flange to move the toilet back 1.75". I am putting in a tile floor with a heating element in the mortar, raising the finished floor about .75" from the concrete subfloor.

How should I cut the stub? How close to the subfloor? How do I ensure a good seal?

Thanks
Jeff

Boulder CO
Home built 1974

Hey Jeff,
Sounds like you have a cast iron stub up. Take a knife and scrape the surface to be sure. I would use a cast iron offset flange to move the toilet position back 1 1/2".

How should I cut the stub? How close to the subfloor? How do I ensure a good seal?
You cut the stub-up off flush wth the finished floor and install the closet flange on top of the finished floor. A wax ring will insure a tight seal. l
Good luck, Tom

Lot of toilets are made in 10", 12", and 14" rough-in. Get 14" rough-in toilet. It is lot easier than moving closet ring.

Home Depot or Lowe's mostly carries 12" rough in toilets. You have to either special order it through these outlets, or go to more professional store where they could have 14" rough in toilets in stock.