Hi,

I am doing a bathroom remodel and this includes moving the toilet to the opposite side of the soil stack from where it is now. I have read all about using Fernco donut etc. to install a new PVC pipe into my cast iron hub but the problem I have is that the current PCV pipe that is attached to the hub (and facing the wrong direction) is cemented into the hub! How do I remove this cemented pipe and get a clean enough hub for the donut? I am afraid of hitting it with a hammer and chisel because I don't want to damage the hub. Should I cut the hub off and use a no hub coupler instead? I want to make sure I get a leak free connection because once I install the floor I will not be able to get to it again.

Thanks for your help.

Brent

Can you post a photo of this connection ? It would be very helpful... Thanks !

I will try to get a picture up tomorrow night. I won't be back home until then. Thanks for your quick response!

Brent



Here is a picture of my problem.

Thank you for the photo. It really helps a lot...

Cut that ABS 90 flat with the concrete. Remove old ABS 90. Take a chisel and easily chip away the concrete from inside of the hub. It doesn't even look like concrete but like some kind of "Fix-All" or "Plaster of Paris". So it should come out easy. But under any circumstances - don't do anything with that Cast Iron fitting. You certainly don't want to break it .

Once clean, get a new ABS Street 90 and Flex Seal (made by Fernco ) coupling. "Street" in fittings means Hub on one end, no Hub on the other end. Measure the Outside Diameter of the Cast Iron hub and buy coupling that fits OVER the hub. ( If your measurement ends up let's say 5 1/2" than buy 6"). The other side of the coupling should correspond with the diameter of the 90 fitting you plan on using. The coupling attaches with 2 s.s. bands. Home Depot may carry such a coupling, depending on size your project requires. You may be better off if you go directly to professional plumbing supply store. They'll have it for sure .

Once the 90 is attached to the Cast Iron inlet, continue with installing new waste pipe towards the location of your new bathroom.

I am enclosing pic of Flex Seal coupling and ABS Street 90 for better visual...

Good luck with your project... and let us know how it went ! Milo

Thanks again for you quick response! I just want to make sure I understand correctly. Do I get a flex seal that will go over the larger "lip" of the hub and clamp down past the lip, or onto the lip? Why is this connection preferred over the "donut" fitting that I have seen others using?

I had a similar idea as to how to remove the concrete. (It is definitely not plaster of paris. I gave it a good whack, or two, with a hammer and screwdriver and it is not going to come out easily). I was wondering about cutting the ABS off at the concrete like you suggested and then using a sawzall with a concrete blade and carefully cutting from the inside outward (towards the hub) to make some relief cuts and then chiseling out the concrete. Do you think trying to cut the concrete would endanger the cast iron hub?

I am going to try and get the pipe/concrete out tonight and I will let you know how it goes.

Thanks again!

Brent

The donut installation is another method you could use. I believe the Flex Seal is better way to go - especially in such a confined space as your photo shows. That's why I suggested it. Yes, it goes past the lip and sleeves about 2" past it, onto the hub itself. There is a stop inside the coupling that will tell you how deep to go. You clamp it past the lip.

Yes, you can use tools, like sawzall. It will make your job lot easier. Just be careful so the hub won't split on you.

We use small Bosh chipping hammer with pointed chisel for such a work. It takes couple of minutes to get it out. You just have to have a bit of skill using the tool and know which angles of contact to avoid so you don't break the cast iron. If you are handy than sure, go for it...

Beautiful! It wasn't too bad once I got the Sawzall involved to cut out the end of the PVC from the cement.

One last question about the flex seal coupler. I wonder about the void that will be created by the taper inside of the cast iron hub and the hub lip. Is there any concern that this void never empties of water, or that it will collect debris and lead to a clog? I don't mind a little extra hard work to make sure this is done right if the donut is a better fix.

The internal diameter of my hub looks to be close to 5.25" and the lip of the hub is about 6.25" and I will be going to 3" pvc.

This should be the last time I bother you. Thanks again for all of your help!

Brent

Ok, you will need 4" Clay x 3" ABS/C.I. Flex Seal coupling. Don't get confused here: 4" Clay actually is about 6" OD. You will stretch it a bit to get over the extra 1/4".

Then, take 12" piece of 3" ABS pipe and insert it deep inside the coupling and inside the Cast Iron Hub. Go as far as it goes into the Hub. Then, tighten up both s.s. bands. Glue your regular 90 on the end of this 3" nipple and continue towards your new bathroom.

If you want, you could get a donut that fits over 3" ABS and goes into 4" Cast Iron. You could just slip in onto the pipe and slide it in. It would act as a seal disallowing water to collect in the Hub area.

Milo