Connecting pvc/fha Drain to Old Cast Stub

Hi Terry.....I was referred here by John Bridge Forums. I'm an old charter member there and I got a question.
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Doin' a shower rebuild here in SE Texas. Customer has an old cast drain & snub pipe that extends about 6" above the concrete. I used a hammer-drill to excavate it a bit....but just dug a trench around it. The old drain has what appears to be a sweated flange on it. I need to modify this for a pvc/fha drain to rest on the old concrete....and trust this, it's HARD! I'm assuming I need to whack it with a hammer and break the old bond to the cast pipe. If so, what then? I guess I need to excavate it quite a bit more and find a way to cut it level. Any reccomendations about the best way to do this? Dunno the size of the pipe, but I need to connect it. I was thinkin' I could use an epoxy on the two materials and then fill the gap with morter or thinset to stabilize it. The HO is thinking more about a fernco coupling....but I imagine that'll take quite a bit more chipping out to even access the screws to fasten it. This concrete is a bear and it's killin' me.

What would you do?

Thanks~~Lazarus

oh, PS~~~I was thinking of simply epoxying the drain to the old pipe. (Good, Bad, Ugly?)

Epoxy would not be an approved method. It needs to be either redone in cast or with transition fittings (Fernco type). If you're worried about the screws, a right angle or flex bit is an easy find. For the concrete, drill some holes through it, then hit it with the rotary hammer chisel. Cutting it (scoring) also helps. If you can dig out under the concrete, that would help as well.

drain

You don't "whack it with a hammer", and you don't use "epoxy or something" to make the connection. You modify, or remove, the riser and then transition to plastic, or something, and install the drain properly.

Fernco it is, gentlemen. Any tips on how to cleanly cut the riser when working below the slab in limited space?

We would love some pictures.

There is an inside pipe cutter ( looks like a 1½" diam. circular saw blade stuck on the end of a mandrel. Works great on copper and plastic. Cast iron will be harder!

From what you have described, this is not a approriate use of a banded rubber coupling. If you have access enough to get that in there, you can probably modify the pipe as needed.

As I said, a picture would be great.

We love your forum over there, and do refer a lot of people over there for help. I hope we can reciprocat the favor for you. Stay with us, and see if we can help you "gittr' done!"

Thanks, Jimbo.....appreciate the input. Like we say at JB Forums, "Pichers...we LOVE pichers!" I'll see what I can do. I know my tile, but I'm beginnin' to think I might be better off with a pro coming in and doing the mods for me. I've used the cut-off wheel before with a dremel to cut the inside pvc pipe for an fha or Kerdi drain, but the cast has me worried.

So, if a Fernco isn't the way to go, how do you guys make the transition to pvc? Just curious....

Oh yeah, we typically send folks over here for all but the most basic plumbing questions...and appreciate the people you refer to John Bridge Forums.

Banded rubber couplings are used for that tranisition. It just seemed like you are in a spot where there may not be the length or clearance available to put that in and torque the nuts.

Looks like a plan, Terry. I'll look into it. Thanx Much!