Seeking advise on Cast Iron waste line replacement options

[Shelbycobra427]

First off, I just wanted to say that this site has been a great wealth of information to me. It's been invaluable on the several plumbing projects I've done myself and I really appreciate the time of the professionals who provide their insight and share their experience.

Background:
The main waste lines in the crawlspace of my (early 1970s) house are cast iron. A couple of months ago, I realized there's a ~15' section of 3" cast that's showing signs of corrosion/leaking on the top of the pipe. I had my usual plumber come out a couple of months ago and he ballparked me at ~$1500-$1800 to replace all of the cast in my crawlspace. It was a little steeper than I was hoping, but not having worked with CI before and knowing how heavy it can be, I know I didn't want to take the job on (no time and a little nervous as I haven't worked with CI before) and I felt it was pretty fair. When he sent the formal quote, however, the final number was ~$3500 with the biggest bulk of it (~$2600) to actually pipe in the PVC. I was really scratching my head on that, since the cost to remove the old CI and the surcharge to work in the crawlspace (quote was itemized) were much more reasonable. The quote included approximately 30 ft of 4", 50 ft of 3" and 30 ft of 2" schedule 40 PVC, so this ends up being ~$24/linear foot. When I emailed him back just to make sure the quote was accurate, he assured me it was, but did offer to knock ~$500 off since I've been a good repeat customer. To me the pricing sounds like they are busy and/or didn't want the work.

I really didn't want to spend that kind of money without a 2nd quote and unfortunately didn't have him
separately quote just the 3" line that really needs replacing, so I mulled over what to do during the holidays. I got a recommendation on a different plumber from my neighbor who had just had a very positive experience. He came out today and quoted me ~$1800 to replace everything or ~$350 just to replace the section that needs it (including pulling the toilet in the 1st floor 1/2 bath to replace all the way to the closet flange. His quote was based on using schedule 30 PVC and non-banded ferncos, but he was willing to use schedule 40 and/or banded no-hub connectors if I wanted -- he would just add in the cost for the more expensive materials).


He talked about how he leaves everything up to code (referring to replacing my softener discharge connection with a properly air-gapped one), yet was planning on using the regular Fernco couplers with no band to connect existing plumbing (mostly existing copper lines from sinks & bathrooms on 2nd story) to the new PVC as well as the PVC to the existing cast-iron line before it exits the foundation. Everything I've read on here suggests that the non-banded fernco couplings are really only allowed in buried connections. Is that correct, or is it something that varies by state (I'm in Michigan in case it matters).

Given the choice, would you spend the extra ~$300 or so to go from schedule 30 to schedule 40? The pipes are in the crawl which should make the noise difference between CI & PVC a little less noticeable, but is there value in going to the thicker sch 40 pipe?

He did say the rest of the CI appears to be in decent shape, but then again, there's no way to be sure except to cut into it. I can afford to replace all of the cast iron, but I guess I'm wondering what you pros would do if it was your house.

Now that the details are out of the way, I'll get to the questions.

1. Do you think it's worth spending an extra ~$1600 to replace all of the cast? I'm not 100% sure that it's in great shape, but it looks OK and,as my wife pointed out, we could always replace the rest later if we need to.

2. Do you think there's a benefit to requesting schedule 40 be used instead of schedule 30? He wasn't 100% sure the price difference of all of the fittings since he mostly uses schedule 30, but he was thinking about $200-$300 extra to use schedule 40. Again, I don't have a problem paying for it, but if there's little to no benefit, I don't want to waste money.

3. What's your take on the Fernco couplings? Should I trust a guy that would normally use non-banded couplings (even though he said he'll use the banded ones if I prefer)?

Any insight is appreciated.

Thanks!

 

[Reach4]

I don't know schedule 30. Did he possibly say SDR 35?

And if you go PVC schedule 40, there is the solid, and there is foam core. Foam core is lighter. I don't have a significant opinion, but you will want to read about that too.

 

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[DougB]

Schedule 40 is the 'normal' PVC, I would use that. The price differential of banded / unbanded couplings is trivial - specify what you want.

Whether or not to replace all the CI - the line will rust from the inside out. Use a camera and inspect the rest of the line - see how corroded it really is.

 

[Shelbycobra427]

I don't know schedule 30. Did he possibly say SDR 35?

And if you go PVC schedule 40, there is the solid, and there is foam core. Foam core is lighter. I don't have a significant opinion, but you will want to read about that too.

I'm sure he said schedule 30. I guess it's allowed in Michigan per code (Another thread I found on this site: https://terrylove.com/forums/index.php?threads/schedule-30-for-toilet-drain.50537/\). However I'm not sure what the disadvantages might be for this application. Just noise?

The schedule 40 he quote was foam core in case that does matter. I didn't ask about using solid.

 

[Reach4]

I would put cellcore into the search box above for some thoughts of others.

Another search would be pvc cell core.

Many of the people here use ABS for drain piping. Its a regional thing with ABS being big in the west. I think PVC is stronger than ABS-- at least I know it more rigid.

 

[Shelbycobra427]

Thanks for the responses. I did some searching on foam core PVC here and elsewhere and can't find anything other than anecdotal rants about how a certain plumber will never use it again after _______. For every one of those, though, there are at least two who say they use it all the time and have no issues. Since all the work is exposed in the crawl space and nothing is to be buried, I'm inclined to go with the foam core sch. 40 and insist on banded couplings.

Schedule 40 is the 'normal' PVC, I would use that. The price differential of banded / unbanded couplings is trivial - specify what you want.

Whether or not to replace all the CI - the line will rust from the inside out. Use a camera and inspect the rest of the line - see how corroded it really is.

Great idea on the camera inspection, but I'm not sure how that would work logistically. If I tell the plumber to come out to just replace the section, but bring his camera and maybe I'll replace the whole thing, I think that's going to be a hassle. He won't know if he's coming out for a 2 hour job or an all-day job. I could get him to inspect the whole line before scheduling the replacement, but the realistic outcomes are an additional $100-$200 bill to inspect the line and either give me piece of mind or tell me I need to replace it all. It's possible there are some areas that could raise red flags, making the decision easy but I doubt the inside of the line looks perfect, so barring any glaring issues, I'm basically back to a judgement call on whether or not to replace.

In the back of my mind, I keep thinking I've seen some of the same telltale signs of corrosion/rust through in other parts of the waste line before when I was in the crawl running cables or an ice-maker line. I'm leaning towards just replacing everything.

I appreciate the help and I'm open to any other suggestions or thoughts. I'll check this thread again before I call the plumber back with my final decision (probably tonight).

Thanks!

 

[Shelbycobra427]

It took me a while, but I just wanted to provide an update as promised. I had the plumber replace all of the cast with sch. 40 (foam core) PVC and banded couplers. There was just one banded coupler that he couldn't find in that size (feeding a 1.5" copper drain from a half-bath into a 2" or 3" PVC branch), so I said don't worry about that one. Looking at the pipe that they pulled, the known "bad" section was severely rusted and gunked up inside, turning a piece of 3" cast iron into one that had the effective inner diameter of about an inch or perhaps less. The rest of the piping didn't look too bad, but I'm not sorry I went the full replacement route. I can rest easy knowing there shouldn't be any issues for years to come.

The only downside was that the plumber added an airgap for the softener discharge (it was improperly directly connected since we purchased the house). I know it's code, but if we have a backup, it will now overflow in the crawl space first....I'd much rather the laundry sink or toilet start gurgling first so we see it. He did put the air gap at the furthest end of the waste line and made the standpipe as tall as he could, so that should help.

Thanks for the assistance.