I have a leaking drain line that I have uncovered by breaking my concrete slab.

A few weeks ago I posted another thread showing the inside of a drain line but the joint between the cast iron pipe and the PVC fitting seem odd because the cast iron section looks higher then the downstream PVC section. Here is a picture I posted in that thread.



I also posted some videos there if you are interested here is the thread.

[www.plbg.com]

Over the weekend I cut an opening in the slab and excavated the section of pipe in question.



To the left you can see a PVC vent/drain connecting to the top of a cast iron elbow, then after the elbow the horizontal CI pipe runs about 24". then connects to a PVC wye, then back to original CI pipe.





Annotated:



You can see the upstream connection has an offset in it - which explains why it looked like that in the picture I posted in the drain camera thread.

The downstream connection is leaking. I haven't taken the whole thing apart yet,

One thing that puzzles me is the wye is PVC yet you can see the whole thing is wrapped in some fabric, it seems someone wrapped this entire fitting in cloth than painting tar or something sticky on it. I don't know why.

My plan is to replace the wye, and all the CI pipes upstream of the wye to PVC.

The pipe runs parallel to an interior common wall between two units. The other side of the wall is all tiled with kitchen cabinets. The branch of this wye connects a line to the kitchen island about 5' on the other side of this wall. I have no access from the other side.

On this side, you are looking at the kitchen space but I haven't installed any cabinets yet. The reason I am breaking the tiles here is this opening would eventually be covered by the bottom cabinets. For this reason I made the cut to about 16-17" out from the wall. On the inside the concrete saw will not get any closer than 3-4". This leaves me a working space of only 12" or so. I am not sure how I would be able to make the cut and connection on the far side of the branch.

I would appreciate any advice or comments in the next day or two. I plan to make the repair over the weekend.



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After removing the cast elbow, you'll have room to stick a reciprocating saw in there, cut the branch pipe and tighten a band coupling.

the fabric is a mystery and will forever remain a mystery. forgetaboutit...
getting things back together properly looks to be pretty easy.
get some red bricks to put under your new work to keep it from sagging.
do use some 4 band couplings as they are more forgiving if the OD's are slightly different.

The branch of the wye connects to a 2" PVC line. I am putting a PVC wye in. I will be using a banded coupling to connect to the cast iron downstream but the other two I plan to solvent weld. Just not sure how easy it would be to solvent weld that branch in and still have the connection to the CI tight and aligned. May be banded coupling at that branch is much less headache even if its between two PVC parts.

sum, you can always use a cast iron no hub wye for the downstream connection. it may fit/align better. then adapt to pvc..

Packy that is a possibility.

All depends on what the downstream pipe looks like. The leak is out of the downstream coupling (coupling #2 in the last pic) so lots of corrosion going on there. My gut feeling is the pipe will be in bad shape on the outside due to 8 years of leaks (the illegal remodel to Tue in the kitchen island by the last owner happened in 2008). I most likely have to make a new fresh cut of the CI pipe further downstream to have a nice round solid connection.

I wish they make PVC no hub wyes with each end extending say 16" long, and you can cut exactly the length you need to reduce the number of joints.

If I do it on the weekend there is no local plumbing supply house I can get to for CI pipes and fittings.

hmm...I stopped at the property for a few minutes tonight, to pick up a few things.

Took a minute to excavate the pipe a bit more. The leak is happening at what I labeled "coupling #2" in the pic, the downstream connection of the wye. The shovel hit that spot gently while I dug and a few pieces of rusted metal broke off. Oh oh...

I guess the rust is pretty bad there. I need to dig further downstream to find a more sound section to cut. I think this may be more challenging then I thought. I quickly pushed the dirt back onto the pipe to keep the sewer gas from entering the living space (it's vacant). I'll take a better look this weekend.

if you can get to a hub, you might be able to get the pipe out of it with the hub still intact. then you can get one of those rubber insert 'donuts', lube it up along with the pipe and gently tap the pipe into it.
this would certainly solve the problem of 'pipe alignment'..

Packy, I am really scared of working with cast iron hubs. I had two previous attempts before and both ended in total disasters. One time I tried to remove a 4" street santee from the hub below, I couldn't free it after struggling for a long time. I didn't want to hit it with a hammer for fear that the broken pieces may fall down deep into the pipes even with a rag stuffed in it. I eventually decided to stick a 2X4 down the santee and rocked it gently back and forth to "tease" it out. I ended up cracking the hub - which after excavating another 2 feet turned out to be the hub of a 4" combo. Another time I tried to push in a PVC donut into an existing CI hub and that didn't work even with soap and whatever lubricant the donut refused to go in and I gave up and cut the hub off. I may have a chance if the hub is facing up and I have full access but with this pipe with this position and angle I doubt I would be successful. I have been diagnosed with having CastIronDonutPhobia and there is no cure.



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Did a bit more excavating this morning. My back is sore from digging at an odd angle so I am going to take a break and continue this afternoon or tomorrow. Going to do something that I can do standing up like replace a few switches.

Here are some more pics. This one starting at the elbow that connects to PVC above the bottom plate.



Further downstream. There is a hub after the fernco connection.



I am inclined to make a cut as downstream as possible because I want to replace as much of this with PVC as I can, and I also think due to the leak the CI further away will be in better shape corrosion wise - I don't know. Here is where I am thinking of making my sawzall cut and put in a 4 band shielded coupling.

go for it.. looks pretty easy..

easy?

well I wish.

I don't know where I heard this saying...

"INSIDE EVERY SMALL PROJECT IS A BIG PROJECT HIDING"

but it's SO TRUE!

I did more excavation, to the right side where I intended to make the cut. Once I free all the soil all the way around the pipe and turned the kitchen faucet on I see multiple leaks.



Feeling the pipe from the underside, I can put two fingers from under INTO the CI pipe.

It was difficult to take pics of the underside of the pipe but here are a few. You can see the big gap.







I didn't go any further. I guess my question is, would this be an indication of what the pipes look like everywhere in this house, or is this just this section because (1) it's the kitchen line and most likely have the harshest chemical put down it over the years, and (2) after they tied in the wye in 2008, the leak has been there and that leak accelerated the corrosion of the CI pipe near it?

Since the crack is quite big I don't want sewer gas entering from the pipe, I wrapped the cracked section with a plastic bag and taped the bag. You can see from the picture below where the pipe has rotted through.



The last 6" or so there is no crack, but I don't know how brittle it is, and whether I may collapse it when I make the cut.

i have 2 words for that situation...
YIKES...YIKES...
if you cut with a sawzall it shouldn't break.
i'd be tempted to slide a few all rubber fernco couplings all the way down the pipe. butt them together tightly and clamp them securely. sorta like a rubber sleeve.
probaly is a waste of time and money but they might help what you have left there. make the end one a 4 band for the transition to PVC.

Packy, are you saying to leave the section of pipe even though it's rotted through at the bottom but sleeve them with rubber Ferncos?

I am thinking of cutting all the way to the right, as far as I can where the slab cut opening allows, and replace all that with PVC, see my pic below where I now plan to make the cut, which is about 6" from the edge of the slab cut, the idea being if I mess up the cut or the cut collapse the pipe, I can try again two inches down again, and that gives me several shots at it.



The question remains how bad would the rest of the lines be? Will they be in similar shapes or better or worse? I am not sure a camera job will tell since the bottom rotted out like this is going to just look like a typical cast iron pipe with build up and debris inside right?

Also, once I make the cut to connect to PVC, with a 2" four band coupling the bands are supposed to be torqued to 60# (or may be 80# I don't remember), do I dare torque it to spec? It may crush the weakened pipe?

Sum, if the CI pipe crushes from a band clamp, it's got to be in really bad condition and you'd see that when you cut it.

urgh...my slab opening width of 12" is not wide enough to fit my sawzall across to make a 90 degree cut. I need to dig a lot more to create an overhang to fit my saw.

OK finally made the cut. Good news is the pipe to the far right seems OK.

This is the underside of the section I cut out, pretty bad.



I made the cut about 6" from the edge of the slab cut, and this is the pipe that I will be connecting to.







Upstream from it is the PVC wye, turns out it is not a wye but a 2" combo (TY). It is completely wrapped with some cloth/fiberous material. Took me a while to pull them off. Still have no idea what purpose that serves.



This is the stuff that's wrapping the entire combo, even the PVC connecting to the branch as far as I can dig is wrapped in it.



It was very difficult to remove the Frenco couplings on both ends of the PVC fitting because whoever put it together used PVC primer and cement to glue the rubber Frenco and PVC together, then the steel clamps, then wrapped this black stuff around it.



I am trying to decide if I should keep this combo, or cut it off and put in a new combo (or 45+wye). If I cut it off I have to introduce an extra coupling further up that branch which I must do blind because of the tight space.

I have been trying to think of a reason why the section of cast iron pipe there has rotted through and 12" downstream it hasn't.

If I look at the CI pipe I just cut, there is a lot of buildup inside, so much that I think it seems more like the I.D. of a 1-1/2" pipe instead of 2". When they put in the new PVC combo, the I.D. of the PVC pipe is larger in comparison, so it is like draining a 2" pipe into a 1.5" pipe, and water stayed at the bottom of that fitting all the time, accelerating the corrosion of the connecting CI pipe. Possible?

By the way, I wanted to mention this sawzall blade I used.

I have always used Lennox diamond sawzall blades to cut cast iron pipe, they work pretty good. So this time I used one again. The position of the sawzall is awkward because the access hole I cut is narrow and I was bent over. It was slow going and five minutes in I have only made a dent on the top of the 2" CI pipe with the Lennox blade. Now some time ago I had purchased a Diablo "Extreme" Carbide Tipped sawzall blade to cut some wrought iron fence railing, and I remember it also claimed it can cut CI. So I swapped out the blade and wow, it went through the entire pipe in about 90 seconds. In fact it went so fast I was convinced the bottom of the pipe must have fallen off instead of being cut through. This blade works fast and I was using a used blade that I have cut two dozens of railings vs a new Lennox diamond blade.

I took a close look at the teeth of the blade I don't see any "grit" on it like a diamond blade but it works.