Just bought a new home, and we're planning on doing some renovation. One area of concern is the cast-iron stacks in the basement: we want to eventually finish the basement, but if these are liable to cause problems down the road we'd rather get ahead of the issues since they'll be encased in walls.

One of the stacks - I'll call it "primary" reaches all the way to the roof; I see it in the attic. It services the only full bathroom, and nothing else right now.

The other stacks - I'll call "secondary" - does not seem to reach into the roof, I see a small pipe in the attic but it's maybe just a little vent? It's definitely not the same diameter as the rest of the stack, and seems to go horizontally out toward the backyard. Couldn't get good pictures of it without crawling into asbestos-land, so I'll hold off on that unless it's really necessary. It services the kitchen on the main floor, and a single toilet, utility sink, and clothes washer in the basement. This stack has what might be a "barnacle" or "wart" on it? I've heard them described but what I see doesn't seem to match images I've found online.

I've included pictures of the stacks in question, which mostly look good (to my untrained eye) but might date back as far as '52 when the house was constructed.

We're also going to want to rotate the PVC bathtub drain going into the primary stack to make it easier to enclose in a wall, is that going to be an issue?

Primary Stack top: Primary stack top

Primary Stack Bottom: Primary stack bottom

Secondary Stack Top: Secondary Stack Top

Secondary Stack Potential Barnacle Detail: Secondary stack potential barnacle detail

Secondary Stack Top (alternate angle): Secondary Stack Top (alternate angle)

Secondary Stack Bottom: enter image description here

Additionally, I know our electric is terrible - and if we touch things to make modifications, we'll have to bring some other parts up to code. Are there similar issues with these?

Finally: if we need repairs/replacement, are we more in the <$1K range, the <$3K range, or higher?

  • Just a comment, since I know (unfortunately) very little about plumbing. Regarding the electric: (a) post a new question with a picture of the existing panel(s) and some details such as: are most receptacles grounded? where (if anywhere) do you have GFCI/receptacles? what major appliances are electric (oven? cooktop? water heater? dryer?), what type of HVAC? In most areas, you don't have to upgrade parts of the electrical system to new code unless you are working on those parts, which makes a big difference. But the devil is in the details... Apr 25, 2023 at 17:53
  • @manassehkatz-Moving2Codidact Most everything is 2-prong (despite there being in-wall AC units that require 3-prong that they HAD to be using unsafely) and scares me. I don't trust any of it, and I want to upgrade to 200A service and relocate the panel anyway, so I'm ripping it all out.
    – user112697
    Apr 25, 2023 at 18:03
  • 1
    "Ripping it all out" will almost certainly require putting in GFCI and/or AFCI on almost every circuit. Which gets expensive. An upgrade to 200A (did it last year, 1950s house) with the panel in essentially the same place (which is what I did) does not usually trigger those requirements except on circuits that get replaced or changed in other ways. If you really need (or want) to relocate the panel (outside to inside or from one room to another) then it is a different story altogether. As far as grounds, you might find, as I have, that grounds are available in most circuits and that you Apr 25, 2023 at 18:07
  • 1
    can replace 2-prong with 3-prong grounded without having to run ground wires or new cables. There are other ways to deal with grounding as well, so "rip and replace everything" may or may not actually make sense. Apr 25, 2023 at 18:07
  • 1
    @manassehkatz-Moving2Codidact I know about the AFCI/GFCI requirements and I'm planning on meeting them, even if it gets expensive - I can do most of the work myself and have familiarized myself with the electric code quite a bit in the last couple weeks. Relocating the panel is basically a must since the current location prevents us from finishing the basement, so... rather have the peace of mind that it's done right.
    – user112697
    Apr 25, 2023 at 18:09

1 Answer 1


There's no easy answer to "Should I replace my cast iron waste stack?". Their average life span is 80 to 100 years. Yours is 70 ish years old. Some parts of it may fail tomorrow, or the whole thing may last another hundred years.

So you take a gamble.

If you replace the basement portion of it now, and if it would have lasted another hundred years, you've wasted a few thousand bucks.

OTOH, if you leave it alone and it develops a leak in 15 years, it's not a big deal to open the drywall box you've build around it. That's a small extra cost. It looks to be in pretty good shape. So maybe leaving it is the right bet? That's a question not a decision.

OTOOH ... if your squishy bath tub is directly above either of these stacks, and you'll be replacing that tub soon, that changes the equation. If you're opening walls and floors and have access to parts of the stack both above and below a floor .... and that stack is 70 years old ... you're unlikely to have another good opportunity to replace it without doing MAJOR damage to your home, during your lifetime. And yet ... it seems to be in pretty good shape, and you just bought a house, so are you really looking for "best practices" that will suck another 15 grand out of your wallet? Again, that's a question not a decision.

I hope this helps a little.


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