Have to replace part of my sewer line...

Old 02-07-19, 06:47 PM
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Have to replace part of my sewer line...

The inside portion of my sewer line is 4" cast iron, it wraps around 3 walls to the stack on the opposite wall of where it exits the basement. there are considerable almost leaks along the entire length, little piles of stinky rust, i am totally broke so out of economic necessity i am going to tackle this myself. I would like to do this in steps rather than all at once but i have a concern, a question, Im hoping to get a few opinions on. Can I leave the stack in place for now & just replace the 70 feet or so of leaking 4" line wrapped around the basement? PVC & working with it is not a concern. Single story structure so that stack rises maybe 10 feet.

the line is supported by iron bars protruding from the block wall every 5 feet or so. if i wedge a couple 44's where the red marks are then cut where the white mark is, will that hold up. also there is the original iron rod support at the very end of the pipe. I was hoping NOT to have to start at the stack, thats a bit more complicated. that piece there is rusty yes, but appears solid, responds well to a mallet. So, do you think i can replace this line but keep the stack in place (for now)?

I really appreciate knowledgeable responses, the picture came out blurry for some reason but will hopefully suffice. Thanks for any help

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Last edited by PJmax; 02-07-19 at 09:12 PM. Reason: enlarged picture
Old 02-07-19, 09:20 PM
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I've seen postage stamps bigger than the picture you posted.
It's ok..... we get the idea.

So, do you think i can replace this line but keep the stack in place (for now)?
That cleanout doesn't look in very good condition but we'll take your word for it.

I would build a crib under that stack using something more substantial like blocks. Even cinderblocks. You need something substantial that won't kick out. 4x4's propped up will be too wobbly.
Old 02-07-19, 10:20 PM
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So, do you think i can replace this line but keep the stack in place (for now)?
Just be prepared for the worst, once you start tearing into the pipe no telling what your going to find or how the connection between new and old will perform!
Old 02-08-19, 12:27 AM
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So then, without saying as much, you'd suggest starting with replacing the stack then working down the line from there. Well that's why I posted this & now I see that's really the best approach. Hey thx for the input. That it would fall I never even considered I was more concerned about the downward pressure all that iron would put on pvc. Yeah, I gotta go top down I guess
Old 02-08-19, 05:37 AM
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I have had some luck using metal strapping to support the cast iron stack. Many times the stack is supported at a couple places along it's height so it doesn't want to fall but sometimes it is supported by the pipe below so you need to be careful. If you are considering replacing everything above I would start from the top or just bite the bullet and do it all in one weekend. If you decide to just do the easily accessible stuff at the bottom make absolutely sure you support the stack well. If using metal strapping it must be absolutely tight before removing the piping below. If it shifts down even the slightest it can break hidden connections above.
Old 02-08-19, 07:02 AM
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Originally Posted by okayday
So, do you think i can replace this line but keep the stack in place (for now)?
Yes, if you brace the stack sufficiently, you can replace the in-basement laterals and leave the vertical pieces in place. Laterals rust-out more than stacks, it is possible the stack is serviceable when the lateral is rusted out. .

The photo shows that there are 3 sections of the stack that are vertical and have collars.
green swishes

<iframe src="https://drive.google.com/file/d/1i3P53VhtYINEoW8lWtsDxDYLGEaUCWI9/preview" width="640" height="480"></iframe>

The cheapest way to proceed with what you're thinking would be to construct a masonry pier (scrounged bricks/pavers/concrete block) or wooden cribbing (use pallets / pallets cut in half) supporting the stack at the green points.

BTW, when you're removing the lateral, do that in sections, but make sure to support each section-junction with a quickly nailed together 2x6 "sawhorses" at the yellow points.

However, If I were you, I'd find a friend-relative-acquaintance who does autobody work; buy them a case of beer and unlimited wings/burgers/tacos, and have them apply fiberglass patches OVER the weak points. This should buy you another 3-5 years before you have to replace the laterals.

Last edited by Hal_S; 02-08-19 at 07:24 AM.

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