Replacing copper sewage stack, copper above ground, clay below. Pictures attached.Removal questions.

[TunaBreath]

The sewage stack at my parent's house is 3" copper and has been replaced in pieces due to sections becoming thin and developing pinhole leaks. I snaked a bore-scope camera through the cleanout (in the photo below, the camera lens is looking back up through the sewage stack, you can see the clay pipe in the right of photo) and it seems that the sewage stack is copper right to the cement floor and then it is inserted into clay pipe? How is the copper connected to the clay? from the photo it seems that it is just a "press fit" as I see no lip from the copper. Any ideas how to go about replacing? Right now I am wondering if I can just basically cut the copper above the floor and then possibly "peel" out the thin copper from the clay. Would be replacing with PVC but as far as connecting the PVC to the clay, I am wondering if it could be a press fit (with added silicone) or if I would have to break up the concrete floor around it and use some type of coupling. Any help or guidance is appreciated.

 

[Reach4]

Clay (terracotta) drain tiles have a belled side. A pipe was inserted in the bell, and the space was usually sealed with something -- rubber gasket, oakum, or mortar maybe. Anyway have two ideas. The copper may have been put in the belled end, and the seal and bell would not be visible from inside. The other is that a rubber coupler was used and the copper pipe was inserted beyond the center.

Is drain2.jpg showing a horizontal or vertical section?

 

[Sponsor]

 

[TunaBreath]

Clay (terracotta) drain tiles have a belled side. A pipe was inserted in the bell, and the space was usually sealed with something -- rubber gasket, oakum, or mortar maybe. Anyway have two ideas. The copper may have been put in the belled end, and the seal and bell would not be visible from inside. The other is that a rubber coupler was used and the copper pipe was inserted beyond the center.

Is drain2.jpg showing a horizontal or vertical section?

There is no bell visible from above ground or it is covered in concrete.

Drain2 shows a vertical section. I bent the borescope into a "J" shape so you are looking back up vertically towards the vent of sewage stack.

So assuming it is sealed with concrete , aor oakumn acceptable repair would be to insert PVC pipe into bell end and pack with oakum or concrete? I just think I would be able to see the gap between the lip of the copper pipe and the bell end of clay pipe unless it is a really tight fit. The other drain pipe in this home is copper pipe inserted into bell end of clay and packed with mortar, although the bell end of that poor is above ground.

 

[Reach4]

How far below the floor is the transition?

 

[TunaBreath]

How far below the floor is the transition?

That's a good question. I'm guessing 3-4". I guess I'm wondering if this repair can be made without demoing any concrete.

 

[Reach4]

That's a good question. I'm guessing 3-4". I guess I'm wondering if this repair can be made without demoing any concrete.

I expect you would be better off to break some concrete. But can you do that without breaking clay? Hmmm. I am not a plumber.

 

[wwhitney]

I think this is the kind of repair where you try to do it the easy way, but need to be prepared to do it the hard way. The easy way being without disturbing the concrete and clay pipe; the hard way being to break out concrete and a section of the clay pipe until you can get a clean end of clay to attach a rubber coupling to.

Cheers, Wayne