Cast Iron waste stack is seeping

[fish]

Hi everyone,

We own a rental property, built in 1950 so some of the systems are nearing the end of their life expectancy. For example, the waste stack in the basement is seeping a little bit, so it needs to be replaced. My question is, what should it be replaced with, cast iron or plastic, and what should I expect to pay for this? How big of a hole needs to be cut into the basement floor?

Thanks, Fish

[DanG]

I guess I do not understand what is weeping. Cast iron is not past its prime in 50 years. Cast iron can have problems, usually caused by chemical drain cleaners and mineral deposits. You or a good plumber would need to decide what is going on with your cast iron. It may need a small section replaced.

Both for repair and replacement, I think any plumber will recommend pvc. It is faster, quicker, cheaper, and easier. Cast iron is still used, especially in commercial and high end work. It can be argued that it is quieter, but you will pay a premium for its use.

(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) [e-mail]

[Speedy Jim]

Cast iron can exhibit corrosion before its usual

100 yr service life. It's primarily due to silicon particles in the iron (not a chemist). The result is a "porous" pipe.

PVC can be used as a repair section (if allowed by the city). Note that the entire stack weight must be supported securely while the bad parts are removed.

If the section going into the floor isn't too badly damaged, it may be possible to avoid digging.

Jim

DanG wrote:

[fish]

The waste pipe itself is weeping moisture. its in the basement, and from the ceiling to the floor there are weeps and solidified weeps that are all up and down the pipe.

Can the whole waste line pipe in the whole home be replaced? Or should you only replace what is exposed in the basement?

Fish

[Don Young]

[fish]

I hope you are right, that it is not possible.

Fish.

[Heathcliff]

Something similar happened to me a few years ago, although (a) it was the upper part of the cast iron stack that was most affected, and (b) it was 75 years old. However, yes it was rusted out from the inside and basically it was time to replace the stack. I sprung to have new cast iron put in up to the level of the highest fixture (pvc above that) for the soundproofing issue. Basically, so if the toilet was flushed or tub drained upstairs, it wasn't obtrusively obvious downstairs. In my opinion the difference between iron and pvc is significant in that regard. My advice would be:

1. Do some more diagnosis. Where is it leaking from? Could be a bad joint, or might even be condensation. It's actually a little young to be corroded through. Try to find the highest point that is wet. Poke it with something -- can you poke a hole in the pipe? If the pipe is sound but there's a bad joint you might be able to solve it with caulk or epoxy or something.
2. If the pipe is indeed bad, consider using cast iron for the above mentioned reason. On the other hand if it's a one story house and the basement is unfinished then soundproofing might not be a big issue. We got wildly varying estimates from plumbers for doing the cast iron

-- but found someone to do it for a perfectly reasonable price in the end.

[fish]

heathcliff,

thanks, can you remember what the price was or there about?

Fish

[Heathcliff]

I think it was about $1200 to run cast iron from the basement floor to the floor of the second floor (actually just below it, where the toilet connected). So about 16 ft. of 4 inch pipe installed. They used the time honored oakum and lead method for the joints. I did all the plaster repair myself afterward. I had gotten one bid of almost $10,000 for the same job! I think that outfit just didn't want to work with cast iron. -- H

[fish]

Hm, thanks.