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Damaged cast iron plumbing

Posted: Sat Mar 31, 2012 8:15 pm
by JRC
Today, I worked on demolition in the bathroom, and I'm still not sure if I'm done. :(

Last week, I had a plumber come out to inspect the house, and give me an estimate to fix the plumbing. At the time, I thought most of the work would be replacing the supply lines. I naively assumed that only the straight runs of the cast iron drain piping had to be replaced.
I assumed this, and the straight run in the basement, were the only damaged pieces. (this is the back parlor, BTW)

I had taken out the rusty, cracked pipe in the picture above up to the ceiling late last year. But, when the plumber looked up during his visit last week, he noticed that there was more damage above that. Uncovering that damage is what I did today.

The pipe from the first floor is on the right. The toilet/sink/bath drains connect to this piece. There was an "S" bend connecting this to the vertical pipe on the left.

Toward the top, there is a "T"--with the side rotted out--that receives the vent for the toilet and/or sink. Above that, is another "S" that leads to, what I think/hope is, the final run of the vent through the roof.

A close-up of the "T" and "S." They both need replaced, and I'm worried that I'll have to remove more plaster to get better access to everything.

I posted most of this in my progress thread. But, the reason I'm starting a new thread is because I have no knowledge about working with cast-iron, and am wondering how much, if any, of this can be saved. Will I have to start smashing plaster in the bedroom to gain access to the final stretch of pipe through the roof? Should I take out the bathroom wall where the toilet and sink go, to be sure their individual vent pipes are intact? Will I have to take up the floor (or remove part of the back parlor ceiling) to make sure the drain from the tub is OK? :o

The plumber will come back, of course. And, I'll get a couple more estimates. But, they are going to be more likely to say "rip it all out" than the posters here.

Thanks in advance for any thoughts.

Re: Damaged cast iron plumbing

Posted: Sat Mar 31, 2012 8:24 pm
by FamlyFarm
In my experience, cast is hard to repair right and costly if you dont know what you are doing. For piece of mind as I found many cracks in my pipe, I removed all of it (4in) and am replacing it with the code approved PVC (3in) this gave me more room to run new access lines without drilling more holes. As i am sure you have found out cast is very heavy and not fun to dropped down a wall haha, luckily mine was only a straight shot. Good luck with what ever you choose.

Re: Damaged cast iron plumbing

Posted: Sun Apr 01, 2012 9:15 am
by sooth
If you do replace it all, be sure to bring the pieces to a scrap yard for some $$$. Metals have gone up in price quite a bit. Often, when removing it, you just need to smash it all.

I also think that replacing with ABS is the way to go. You could even do this yourself if you want. Working with PVC and ABS is pretty simple if you're good with measurements and accurate cuts (it cuts easily on a saw or with a hand saw). Just dry fit everything first, and remember that you have only 1 shot when gluing it.

Re: Damaged cast iron plumbing

Posted: Sun Apr 01, 2012 9:53 am
by JRC
I'm not so worried about replacing with PVC, if I need to. (AFAIK, ABS isn't an approved material in the US) I'm worried about the damage that would happen to get to all of the cast iron.

I've also heard that PVC is louder than cast iron. Has anyone noticed this, and does it bother you? In my current house, the drain runs in the corner of the kitchen, so the sound of running water isn't out of place there. But, this drain runs through a public room.

Re: Damaged cast iron plumbing

Posted: Mon Apr 02, 2012 7:33 pm
by sooth
I can vouch for that. It's definitely pretty thin stuff and transmits sound pretty well. I currently have a PVC (I always get PVC and ABS confused since they seem like practically the same thing to me) drain/stack that runs through the kitchen. If thetoilet is flushed you hear a huge rush of water. It's currently exposed, since I had to redo some water pipes, but when I box it back up, I plan to fill around it with insulation to help muffle the sound.

Re: Damaged cast iron plumbing

Posted: Tue Apr 03, 2012 7:43 am
by cs
We replaced our center cast iron stack when we added our addition (this moved bathrooms around a bit).

Regarding noise...It is louder than the cast iron was, though not obviously so - the run that moves down through the walls of the living spaces is straight (so that minimizes noise) and is located in an insulated exterior wall (which also helps). Where the noise is significantly louder, is in the basement where the PVC stack meets various elbows to take it to the sewer line. But our basement is unfinished, and extra noise down there is not an issue.

Regarding your vent pipe question... it's a tough call. I would guess that dry cast iron vent pipes should be in better condition than the wet parts of your stack, all things being equal. And I would assume that as long as the vents stay dry, if they have minor perforations, it won't matter much. I suppose you could get some sewer gas released inside the house walls, but if you have not noticed that yet, than maybe that's not an issue. Plumbing inspectors in our neck of the woods drop an Oil of Peppermint solution down the vent pipe from the roof to see if the smell can be detected from inside the house. It's incredibly pungent (this is not the same thing as peppermint extract). You could probably find it online, or at old fashioned drugstores or health food / supplement stores. If you do this, obviously you can't have any "open" ends to the plumbing system, so you might have to get a bunch of those rubber gasket caps to temporarily close off any pipes that have been left open. You should also have the person who mixes and pours the solution down the vent stay outside. Let an uncontaminated person do the inside sniff test. As I said, it's super pungent.


Re: Damaged cast iron plumbing

Posted: Tue Apr 03, 2012 9:11 am
by Lynners
We're in the middle of our bathroom overhaul, and ended up replacing the old cast iron with ABS. I've definitely noticed an increase in the level of sound coming from draining things...but, there's a huge chunk of floor in the living room missing right above the ABS, so that could have something to do with it!

Re: Damaged cast iron plumbing

Posted: Tue Apr 03, 2012 3:08 pm
by JRC
Thanks for the replies everyone!

I think it's best if I overhaul the drain system, and eliminate any cast iron. Unfortunately, that means I'll have to take down a part of the back parlor ceiling, and maybe a part of the front parlor ceiling to gain access to the tub drain. :(

Maybe it would be better to take up the bathroom floor, instead? That would be tricky, though, because it looks like the floor boards are continuous under the walls.


Re: Damaged cast iron plumbing

Posted: Tue Apr 03, 2012 6:54 pm
by sooth
It's very possible that the floor boards continue under the wall, which could cause some problems. As much as it will suck, the ceiling will probably be the better option.

Re: Damaged cast iron plumbing

Posted: Thu Apr 05, 2012 7:35 am
by Texas_Ranger
You can try selling the cast iron, but I doubt it's worth much. Several years ago when copper had already gone through the roof my dad tried to sell some scrap stel (radiators and some other stuff I think) and the guy told him: "If it's less than a ton don't expect any money for steel, but I'll TAKE it free of charge!".
I've also heard that PVC is louder than cast iron. Has anyone noticed this, and does it bother you?
Definitely. I know a place with an exposed PVC stack and every time someone flushes the toilet above (6-storey apartment building) I'm tempted to rush to the bathroom because I expect water to shoot out into the room. This is a completely exposed stack though (I suspect the old cast iron stack had plaster around and they didn't bother to replace that along with the pipe, so they just painted the pipe).