Hi:

I tried to remove a leaking 2" cast iron pipe leading into the 4" cast iron stack, I cracked the stack around the collar where the T joins the vertical stack. The stack runs from the floor of the basement through 2 stories, through a small attic and out the roof. I am guessing it weighs almost 400 lbs.

Other than replacing the whole stack, which would require ripping out floors, walls and ceiling, as well as roof repair, I am wondering what my options are.

Can the cracks in the cast -iron be welded?

I have also thought about cutting the cracked T out and inserting a new plastic T with no-hub connectors above and below, but there is no exposed place ( like another T ) where it would be east to support the vertical stack. I am concerned that if I do not support it perfectly, it might shift when I cut it, causing leaks where the toilet and sink attach to it on the second floor.

Thought, suggestions, experiences?

Any ideas would be welcome.

Thanks,

Charles

well the pvc tee and banded couplings are the way to go . you just have to figure out a way to support the pipe before cutting it. you just want to make sure it doesnt slip down before you get the new fitting inserted.


i would use iron strapping or a riser clamp or both or maybe something else depending on what and how i can attach it to the structure

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PLUMBERS "Protecting The Health Of The Nation"

I googled up 'riser clamp', and it looks like that might work. Thank you.

The place where I need to clamp it is just under the floor joists at the top of the basement wall. I could rest one end of the clamp on the foundation wall, and maybe run a bolt through the other end into a joist that is less than 1 1/4 inch from the stack.

So, if using that strategy, I can be sure the clamp is well enough supported, can I also be confident that the pipe will not slip through the clamp?

Also, it seems if I am going to splice in some pvc, I need a really straight cut. A sawzall sure wont do that. How do I make a clean cut in a 4 inch pipe that is an 1-1/2 inch from a wall (That is, the pipe is 1-1/2 inch. the flanges of the T-fitting are almost touching the wall)?

Sawzall With a Lennox Diamond blade and a good operator will mke a sutible cut in cast

PlumbCat TM 2003


Plumbermandan

and you can use a grinder to straighten it up if needed.

yes the riser clamp will hold for a 100 years (unless it rusts out first) the way you describe mounting it and it will not let the cast slip.

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PLUMBERS "Protecting The Health Of The Nation"

The toilets and sinks on the upper floors will hold the stack while you cut it, and there is nothing you can do to make them start leaking. I am more concerned about how you were able to crack it. Were you being forceful with it or is the cast iron getting weak?

Seeing as XH cast has a life of about 80 years I wonder that too...

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I pulled on the 2" leading into the stack, trying to get it free to replace it. The 2" had rusted through.

I guess I was being forceful, but I was surprised at how easily it cracked.

Is your question suggesting that it might be time to replace the stack anyway?

Snap cutters are the fastest way to cut cast iron. They don't always work though sometimes they crush the pipe. If the cast iron has a lot of silica in it, it is difficult to cut with a sawzall. I have had castiron that ate up blades but snapped easially. I would replace the exposed 4" cast iron while I was replacing the tee. David

very hard to get them around the pipe inside a wall and is why a sawsall was mentioned.

most of us plumbers have done this once or twice or a 1000 times in our careers and know better than to waste time and energy trying snap cutters in this situation

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PLUMBERS "Protecting The Health Of The Nation"

Those snaps and that brittle CI might combine once more to crack the stack some more. Even if scored for quite awhile first.

With the Reciprocating saw it still may be advisable to cut patiently and gently.

Hopefully the stack is not uniformly weakened and you will be able to cut on a stronger spot. You may be able to tap along an area to find the weak sounding and more solid points.

Best of Luck to you.

it is a cracked fitting not pipe

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PLUMBERS "Protecting The Health Of The Nation"

Sorry. I had a pipe image in mind as opposed to fitting.

it is the way the O.P. said it. dont beat yourself up over it

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PLUMBERS "Protecting The Health Of The Nation"

Do others agree with hj (above) about the stack not moving? It sure would be easier if I do not have to secure the stack.

More generally, who has seen a cast iron stack move or even fall when the bottom was cut out from under it?



Edited 1 times.

i have never seen a stack fall when cut because i ALWAYS secure it. why take a chance? brace it with something.

exactly. and yes i have seen them drop atleast an inch

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PLUMBERS "Protecting The Health Of The Nation"

Bad BAD BAd Things can happen I do not even have time to go into.You could cut up old landscape timber and place it under many different locations at the stack hubs or at the fittings near the stack.When you cut this stack the force or weight will come to bear on the blade you are using so be careful of the last 1/2 inch any way.Consider replacing what you must with no hub cast .If you are just replacing a section and fitting it will keep the look sound and feel of the cast that has been there for all these years.Good luck.Next time .Cut the two inch out where it hangs rather than using the ten foot castwrench to try to remove it from the fitting.Good Luck.

You guys have all been awesome with your advice.

I now feel confident enough to try this this weekend.
I am going to brace it really thoroughly and try to snap-cut out the bad fitting. If the cutter wont fit, onto the sawzall.
I realized reading these posts that if I do my cutting on the old fitting, the cuts do not have to be perfect.

One more question (probably not the last): Do I cut the hub off of the four inch below the bad T after I remove it, so I can use no-hub to make both the upper and lower connections. I was think this might be the way to go so that I can cut the new fitting to exactly fit the gap created by the old one. This would let me cut the fitting to exactly fit, and carry the load of the stack down to the lower stack, like was happening before.

Whereas, if I leave the lower hub, I would have to cut the new piece a little short to be able to rock it into the hub. The gap would mean that the weight of the stack would no longer be transfered to the bottom of the stack, but I would be depending on the bracing to hold the upper stack forever.

youll never get that lined up going into the hub. i have tried more than once like an @#$%&...

i really suggest you just get the sawsall or a grinder instead of the snap cutters. especially if you havent used them before. easy to crush the pipe instead of cutting it. plus i dont think there is room behind the pipe without cutting a whole in that side of the wall too.

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PLUMBERS "Protecting The Health Of The Nation"

You will want to cut above and below this tee insert pieces of pipe into the hubs of new tee and replace fitting with short pieces of pipe between the cut in cast piping .with no hub bands.you will need about 1/4 inch larger cut out ,than the new made up fitting to allow you to roll back no hub rubber and insert new fitting.Good Luck.

Not to mention if the snap cutter crushes the pipe, pieces can fall in...and down - look out

On a side note; I usually replace, (or cut in) a fitting into existing cast iron pipe by using a no-hub
cast iron branch fitting then make the transition to PVC, if that's what I'm working with.

e-plumber
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John William Gardner 10/8/1912 - 2/16/2002

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This slow drip will waste 7+ gallons of water per day.

If you knew how hard it is to crack a good cast iron fitting, you would not even ask that question, but might start replacing it.

1. I have never even seen a stack move a little bit.
2. I have never supported a cast iron stack when I had to cut it.
3. The only way it can drop is if every pipe connected to it broke off, or the walls and floors collapsed.

Depending on what is conected into the hub, it could have a bead on it which would make it impossible to slide a No-Hub coupling over it.

At least that is the way it is right now.

1. I have never even seen a stack move a little bit.

> More than a few times.

2. I have never supported a cast iron stack when I had to cut it.

> Not every time...but when deemed necessary.

3. The only way it can drop is if every pipe connected to it broke off, or the walls and floors collapsed.

> 'Drop' a little yes, but never a complete failure.

e-plumber
-----------------------------------------------------------------------------------------------------------------------------------

"The society which scorns excellence in Plumbing as a humble activity and tolerates shoddiness in philosophy because it is an
exalted activity will have neither good Plumbing nor good philosophy: neither its pipes nor its theories will hold water." -
John William Gardner 10/8/1912 - 2/16/2002

Repair your leaking Plumbing fixtures ASAP [www.theplumber.com]
This slow drip will waste 7+ gallons of water per day.

1. I have never even seen a stack move a little bit.

> More than a few times.

And how did that happen, unless ALL the pipes were loose in the wall, AND the openings were at least an inch too big on the bottom.

Cut the pipe with a SawZall. If it is going to settle, the blade will be pinched before you can remove the piece, but it could move a 1/16" just because of inherent compression.

i for one just dont want to take the chance that the stack pipe is heavy enough to come down with or with out breaking branches. why take the risk when you can be safe and 100% sure it isnt going to come crashing down?

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PLUMBERS "Protecting The Health Of The Nation"

what do heirs have to do with compression?
i too support stacks before cutting.

I didn't say you COULDN'T do it, I just said it is unnecessary, But some men wear a belt and suspenders because they also doubt that either one will work by itself.

CharlesP:

Could you post before and after pics? I'd just like to see this stack.

I too would support the stack.

Many years ago we did drop a stack but we planned it that way. It was in a house that we were demo'ing and we thought it would be fun to watch.

The best part of the demo was when we took the upstairs tub out. A tow chain through the window then through the overflow hole did the trick!

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I take the 'belt + suspenders' approach most of the time. That stuff is heavy, and strapping it doesn't take much time or effort.

But if HJ says it doesn't move, I'll give it a little more thought the next time it comes up.



Edited 2 times.

And as an aside. The plumbing codes ALL call for the vertical pipe to be secured at each floor as it passes through it. The lateral pipes normally fulfill that requirement.