Risky Business? Cobbled Up Offset Closet Flange

[Always Something]

We have a ground level toilet that was installed in the mid-70s when the house was built. It has always been a “slow flusher,” taking 3-4 times longer to flush than other toilets in the house. When I pulled the toilet to replace a leaking wax ring, I saw what may be a factor in the slow flushing. A 4x4x2” offset flange, or at least a portion of one, was used in the installation. Where the angled portion below the flange meets the drain pipe, there is a pronounced ledge that must create significant turbulence in the water flow. My layman’s knowledge of plumbing can’t explain how or why the connection was made the way it was. It doesn’t appear that the lower (vertical) portion of the offset flange is present. A white adhesive seems to encase everything.

Homeowner’s bizarre idea: What if I ground the ledge away to smooth the flow? This would involve grinding cast iron, adhesive(?), and, presumably, some concrete. I would then use marine epoxy putty to reshape and seal the joint. I don’t like the idea of grinding into the drain pipe, but the thought of extracting the flange and integral angle section is daunting. (Note that the white adhesive/filler extends beyond the left side of the flange, partially filling the void that originally provided access to the drain pipe.) Would my solution be anymore cobbled up than the current mess? What would a professional do if this was in his house? Or should I just live with the slow and iffy flush?

Any thoughts or observations are really appreciated. Thanks!

[drainman scott]

First the reason why there is a offset flange is because the waste arm was brought up through the slab to close to a finished wall ... should of been 12 " rough opening vs 10" ... I wouldn't be grinding anything unless you want a hole in your pipe.

From the looks of it your CI offset flange looks in good shape I would reinstall the toilet and leave it alone.

There is a alternative but it requires demoing the cement slab and extending or shortening the waste arm 2 " .

[Bob D.]

If you got a toilet for a 10" rough-in you could eliminate the offset flange.

But it could snowball into a real mess pretty darn quick if you've not done
anything like this before.

That offset flange is most likely a lead joint. While that doesn't scare me or
any plumber the average HO will not have the tools or experience to deal
with this.

[Always Something]

The offset is actually to gain clearance between the toilet and the adjacent vanity. I was concerned about lead also (and still am) but so far I’ve only encountered the hard white putty like stuff that’s slathered everywhere. If I could excavate down far enough to get a clean fit of a new CI flange, I would probably call a plumber to do the lead work. I doubt that casting lead soldiers as a kid qualifies me for this. My tools do include a Sawzall, die grinder, etc.

[Cable or root]

Don’t turn a $200 project into a $2000 project. Call a plumber.

[Bob D.]

Agree. It's good to know when it's time to call a Pro.

This could be it.