Replacing CI soil stack with PVC leak issues

[Robert Wirth]

Hello,

This is my first time posting and honestly first time attempting any type of plumbing project so I want to apologize if I use the wrong words/terms. I will attempt to convey my message the best I can.

So here is the situation, I needed to replaced a vertical 4" CI soil stack in my basement due to leaks and small pinholes throughout. The plumbers quoted me at 1300-1700 but this is not feasible due to my financial situation at the moment. I did extensive research before starting and the project went fairly smooth.

I cut out the soil stack with a grinder all the way to the toilet and replaced it all with pvc. All that is left is the 2.5" CI pipe that is remaining in my basement floor. (reason I cut it so low was a CI cleanout was directly above this and I even had to cut that into pieces to save the 2.5" I did).

There is still a leak coming from the connection of pvc to CI.

First I tried the fernco proflex 4" CI to 4" PVC fitting (one with metal sleeve) and it leaked. But i felt the ci in the ground was not smooth enough and even enough so i spent the next hour and made it perfect. Tried again and still leaked

Next I tried a fernco 4" ci to 4" plastic fitting (one without the metal sleeve) and still leaked

So there is where I stand... I knew they were not the same sizepipes but I assumed these fernco fittings were meant to overcome this. I have since re measured the pipes and I assure you they are not the same OD. The CI OD is 4 1/8" which I am aware of is the same size as copper from this previous thread https://terrylove.com/forums/index.php?threads/leaking-fernco.36260/ and I need a copper by cast iron mission coupling with the shielding as terry says in his one post.

Does this mean I need a copper to pvc fernco fitting so the sizes are correct?

https://www.fernco.com/specifications/pipe-material/plastic-connecting-to-copper
https://www.menards.com/main/plumbi...-4-pvc-st-xhci-x-4-cpr-proflex-coupling/3007-
44/p-1444430438088.htm

is this the right one? (one link from fernco website one from where to buy it)

One last thing. There is some torque on the pvc pipes because the toilet flange is not directly overhead of the soil drain in the floor. The pipes do sit flu once fitted together, could this also cause an issue with leaks?

I appreciate all help and advice. I know I am no expert and I have redone pieces of this a few times but I am learning

Thank you,

Rob

 

[FullySprinklered]

I'm not as crazy about the no-hub connectors as some of the other guys on here. Last three times I used them, I had leaks. Replaced them with a regular Fernco and the leaking stopped. There's more to tell, but I'd like to let the screaming subside before I elaborate.

Purple primer still sucks.

 

[Sponsor]

 

[Reach4]

Does this mean I need a copper to pvc fernco fitting so the sizes are correct?

I would think so. I would use some kind of lube. Maybe a pipe dope safe for rubber. Maybe silicone grease. Maybe just dishwashing detergent to try to get the rubber to flow into the imperfections before the dish stuff dries out.

I would think there would be something better than the dish soap. I am not sure what I would go with.

Torque the hex to 5 ft-lb... about what you can turn a nutdriver to when you try hard.

I am not a plumber.

 

[Terry]

The copper to plastic is what you can use. It's really hard to get the other ones to fit when the pipe is copper sized.
And alignment is important.