Cast Iron Vent/Soil Stack replacement?

[BuckeyeC]

I have an older house that was built in the 1940s. The 3" vent stack/soil stack and drain pipes are cast iron.

I am considering having the iron drain pipes (tub, 2 sinks, and toliet) replaced as it appears there is rust on them and they may be developing a slight leak.

1. One plumber wants to replace all the drain pipes as well as the entire vent stack for $1800 (upgrade to PVC). This would be a complete job from the drain in the slab all the way up thru the roof.

2. Another plumber wants to replace only the drain pipes with PVC and leave the vent stack as is. He suggests if there is nothing wrong with the vent stack then it probably doesn't need replaced as no water runs thru it. He wants to charge around $400.

If I go with option #1, there is no way of telling if the vent stack can be pulled down thru the floors with no problems - this job may involve cutting holes in the wall to get to the stack.

A visual inspection of the vent stack in the attic-it appears ok and I have no problems or leaks with it currently.

Should I leave things as is and replace only the drain lines (#2) ...or should I also replace the entire vent stack as well (#1)??

Thanks in advance for your help.

 

[FloridaOrange]

I would only replace what needed to be replaced. You (or your plumber) should look at the rest of the system to make sure more work isn't needed on the system. IMHO, messing with roof penetrations when it isn't called for isn't too bright. Not to say that plumber #1 couldn't do the work and you wouldn't have a problem but if you do end up having a problem and have to get them or someone else back in to properly patch your roof would make you a very unhappy camper.

That being said, I believe there are tests for cast iron that would tell you if the stack needs to be replaced *continuity tests, please someone correct me if I am wrong*. The pipe may or may not be corroding from the inside out....

 

[Sponsor]

 

[Master Plumber Mark]

drain line only

most likely the vent stack will be there for another
50 years without any troubles....

I would not fool with that stack going up through the roof

just cut it off above the ideal tee and re do everything
to the floor....

$400 is an ok price......