DIY Question: Replace Partial Cast Iron Sewer Stack

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cmacnichol

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Hello All,

I have an old house, build early 1900's, that has an old cast iron sewer stack going to the first floor bathroom. Unfortunately it seems that the line is having a lot of draining issues and no amount of drain cleaner or snakes have helped. At this point I have decided to just go ahead and replace the stack with an all PVC one.

My question here is, how hard of a job is this and is it something that I can do myself? Plumping has never bothered me, but I have never done a main sewer stack before.

Luckily, after looking at it closer it seems that work has done on it in the past. The main sewer line coming into the house is PVC and it hooks into a another PVC Y before transitioning to Cast Iron via rubber sleeve.

My other concern is that this line currently does not have any kind of vent in the system that I can find, so that will need to be added as well. The attached image should explain how it is currently a lot better then I can.

The only other thing I am uncertain about is an offshoot from the top is hooked to an older cast iron tub, I have NO Idea how to unhook and install a new drain on that.

Thoughts? Advice?
 

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hj

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Well, the PVC looks like it was done by a handyman or DIYer. ANY vents would NOT be visible in the basement so you don't know if you have any or not. VERTICAL cast iron lines seldom "have problems" so your diagnosis may be faulty. Call a plumber.
 

Terry

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Well, the PVC looks like it was done by a handyman or DIYer. ANY vents would NOT be visible in the basement so you don't know if you have any or not. VERTICAL cast iron lines seldom "have problems" so your diagnosis may be faulty. Call a plumber.

The large 4" lines tend to be okay.
Normal areas to give troubles would be at tub drains, lav drains and disposers.
Like hj mentions, most of the venting is higher.

dwv_b2.jpg
 

cmacnichol

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Well, that diagram helps. Shows me what I don't have at least and how it is supposed to look like. Currently, there is only a single bathroom in the house, with the kitchen sink and the utility room drains all leading directly back to the Stack. Tracing those lines I was unable to find any kind of air vent.

A thought here then, my draining problems, I have always had them. Could it all just be from not having any vent at all in the system? Can it even WORK without a vent?
 

cmacnichol

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Also, as to calling a plumber. I have another coming out for a quote. The first one however gave me a quote of 5K to completely redo the stack and the other drain connections... Just trying to get an idea here if this is something I can do myself (If I even need to if there is no vent) or what it SHOULD actually cost.
 

Reach4

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Unfortunately it seems that the line is having a lot of draining issues and no amount of drain cleaner or snakes have helped. At this point I have decided to just go ahead and replace the stack with an all PVC one.

What are the symptoms of your "draining issues"?

You have a 2 inch cleanout/access on that cast iron-- small for a cleanout, but it can be useful. It seems to me that could be used to tell if the problem is above or below that point. That plug is probably brass, and you may need to use hammer on the wrench to unscrew. If it does not unscrew, use hammer and chisel to get it out. Replace it with a PVC plug. https://terrylove.com/forums/index.php?threads/cant-open-cleanout-cap-got-any-advice.17943/

Your PVC job does not look right. You would have thought they would have added some significant support for the cast iron above before cutting away the lower part. That PVC coming in from the left has a trap that is probably not right. And while they were adding that PVC sewer connection, I wonder why they did not take the opportunity to add a cleanout . And they used the wrong kind of sleeve.

Not a plumber.
 

Gary Swart

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Cast iron is very heavy. If you DIY this job, you will have safety issues to deal with. 5K seems like a lot, but not knowing what the job will entail makes it hard to say that it excessive.
 

Terry

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Not being there on the job, and knowing what they plan to do, it's hard to say.
If they are replumbing for the tub, toilet, lav, kitchen and washer, and it's to code, then it's looking good.
Everything should be vented.
Removing cast I normally use a snap cutter. Being able to wrap the chain around it can be hard. The galvanized I can cut out.
 

cmacnichol

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Well, thanks everyone. You have certainly given me a lot to think about and to check into. I appreciate it.

Think I will try the cleanout and see what it looks like first. From what I can tell, I would not have to cut the Cast Iron as the only place it is connected to the stack is that sleeve. The others go to the sink, which is already disconnected and the toilet and tub. Tub is the only one I am concerned about.

I HAD wondered how the Cast Iron was just sitting on the PVC like that. I get the feeling that it is actually the floor above that is supporting it.

Had the house inspected twice before I bought it, they missed so much stuff it is no longer funny.
 

Reach4

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I think you are implying that the symptom was either slow draining of the tub or backing up into the tub when some other plumbing is used. Those would indicate different things.

If I presume that the sink is not in the crawl space :) , that PVC trap should not be where it is. If things are working for that sink, I guess I would ignore that for now.

Regarding that plug, I would have a big bucket to catch whatever might come out. If there is a bunch that comes out, the problem would be below the plug. There is a good chance that nothing will come out, but be ready anyway.

Based on the distortion in that rubber sleeve, I suspect the PVC and sleeve are carrying weight. I would look at adding strapping to the joists to carry the vertical load. But I am not experienced. Maybe ask in your plumbing store about using steel strapping for that.
 

cmacnichol

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The symptoms were as such. Tub would Always drain slowly, where is would be normal for it to back up as you took a shower. The Sick, well it Had worked, but recently stopped draining at all. Which is what started this whole mess. The toilet would occasionsly back up for no reason at all.

Might check the clean out plug, but with what everyone has said, it might just be better for me to look around more for a decent plumber who know how to do this.

Thanks again to everyone for their input. Helped me clarify things.
 
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