Question on Cast Iron toilet run

[Electroguy]

I am remodeling my bathroom and am moving the toilet about 2 feet closer to the main stack. The entire system is done in 4" CI. The horizontal run will need to be shortened by about two feet as the run is simply a straight shot over to the stack and doesn't go through or around anything.

My question is if it is better to put it back with oakum and lead or if I should use one of the rubber gaskets.

The horizontal run is currently about 4 feet long. I was planning on simply cutting the pipe a short bit before the hub on the main stack, melting out the lead and prying out the oakum. I would then cut the pipe to the correct length and put it back, leaving the toilet flange, elbow, and horizontal run intact. The angle will be a bit steeper to meet the correct floor height for the finished floor, as I can't really move the hub on the main stack.

The space that the horizontal soil pipe run is in is within about an inch of the joist to the side and an inch to the drywall of the ceiling below. I can't really open up the ceiling below because it is the kitchen and the ceiling below is one of the continuous ceilings across most of the first floor (about 1000 sq feet). I would need to have it match without showing any areas where it was painted. There is very little room for using threading or caulking irons (which I don't own).

1) For overall quality and security of the joint, is it better to put the run back in oakum and lead or go with the rubber gasket?
2) If I put the run back with a rubber gasket, I'm concerned about future possible leaks; Is it better or worse to use the better quality (like aquarium grade) silicone sealant on the gasket when putting it together?
3) If I should put it back in oakum and lead, is it possible to caulk a horizontal joint on the backside blind (the area between the joist and drywall) and do a good job?

Your comments, criticisms, and help would be much appreciated.

 

[ExtraMilePlumbing]

I would use a 4 strap band those have never failed me before.then use a abs piping/flange..

 

[Electroguy]

What would be the advantage to going to ABS when I already have all the parts in CI?

I would take it that you are suggesting that I cut a section out of the middle of the pipe to shorten it and use one of the 4 band rubber couplers to seal it. I like that idea as it would make it much easier to work on.

Once I put it together (and test it for a water tight seal), the space will be closed off and not readily accessible without opening up the ceiling in the kitchen. Will those 4 band couplers stay sealed for 30+ years for a closet run, even if there will be the usual motion and vibration that takes place in a typical building?

Thanks.

 

[Electroguy]

Also, would it be wrong to use high grade silicone caulk with one of those couplers or do I create more problems?

 

[frodo]

sounds like you have made up your mind, do as you wish

extramile is speaking from experience,

you stated yo have no room under the pipe? maybe an inch?

do you own cast iron chain cutters? will the old pipe crush
when chain cutters are used?

I would cut with grinder, or sawzall, depends on the pipe

cut the old crap out, disgard, replace with brite shiny new stuff. use a CI to Pl mission band


no silicon, if you want to seal the band, use black swan no hub band sealent

 

[Electroguy]

I'm looking for advice from people more experienced than myself. I'm trying to see what options are available and explore them. My questions are based on my own fears and trying to analyze them. I don't easily just accept what others suggest, but try to ask enough questions to get to the point of understanding the why behind the suggestions. I hope I haven't offended anyone - I don't want to do that.

In terms of cutting the pipe, you are right that there really isn't enough room for the chain cutters. I was planning on using one of my carbide Saws-All blades. I've done that before and know that it takes a little bit of time, but it's not a difficult thing to do - just need patience.

In terms of using all new in plastic from the cut up to the toilet flange, that would be very easy to do and the cost isn't very much, I was just asking as the original cast iron parts are in great shape (it is only about 15 years old and saw almost no use). I was just asking what would be best and why.

Thanks for the feedback.

 

[frodo]

I love cast, been installing it for years, love the look, makes for a pretty job
when I started out in plumbing we leaded joints, I still have my running ropes and irons
along with a huge ladle. The plumber that trained me, refused to install abs pipe. said he would be fired first.
my little radical arse was right next to him. times change.
he is dead now. would totally freak out over pex. thought about digging his old butt up and telling him

pvc is a better product, cast rots after years of use, gets rough on the inside and catchs hair/soap scum.
anytime you can cut it out and replace. do so.

do not forget, cast and plastic are different OD measurements. you need a ci x pl mission band
when you screw the flange to the floor, use brass screws. the acid in urine eats metal/rusts it in a year or 2

 

[Electroguy]

Frodo, Thanks for the advice. I will most likely then put the run back in PVC.

I plan on building in some very solid support for flange and floor around the toilet. I don't want any opportunity for rocking, flexing or other issues. I just wanted to make sure I wasn't missing anything.

I appreciate the help.