Repacking an inverted oakum / cast iron 4" joint on a sewer stack?

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How, and who, can still repair old oakum joints that are inverted.

Situation is a 4" CI waste stack comes down from the roof above the top floor toilet in an condo.
Just above the toilet, it branches downward for the tub.

The walls and everything are all finished. mostly with tile. The three story building was built in the 1940's and moved in 1966 to the present location.


A toilet wall wall got opened up a little for another reason.
The issue is that water from rain or fog apparently comes down the stack, and hits this joint, creating a persistent rusty spot:
PXL_20220721_191736407.jpg


Can the old oakum/lead be applied to inverted joints?
Is there another way to repack that joint?

The other cast iron appears to be in good condition. The little section pictured is only 4" long, and is galvanized, the rest is cast iron.


How would you approach that repair?
 

Reach4

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Do you see water, or just rust? You might be able to re-caulk the joint, but I don't mean the stuff that comes out of a caulking gun. Caulking a leaded joint involves pounding on the lead with a "caulking iron" or other tool such as a big blunt screwdriver hit with a hammer. I would try that first. Do some reading and maybe use "caulking iron" as a search term.

What some would do is to support that cast iron really well. Then remove the lead and galvanized, and put in a Fernco Donut (or equiv) to transition to plastic pipe. I am not a pro, and I have not done any of that.
 

Sylvan

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Do you see water, or just rust? You might be able to re-caulk the joint, but I don't mean the stuff that comes out of a caulking gun. Caulking a leaded joint involves pounding on the lead with a "caulking iron" or other tool such as a big blunt screwdriver hit with a hammer. I would try that first. Do some reading and maybe use "caulking iron" as a search term.

What some would do is to support that cast iron really well. Then remove the lead and galvanized, and put in a Fernco Donut (or equiv) to transition to plastic pipe. I am not a pro, and I have not done any of that.
What is a "caulking iron"?

I still caulk joints using a "yarning iron" and a Spoon (packing iron for oakum ) and after the joint is poured in ONE pouring I use an inside and outside irons AFTER the lead hardens I use a packing iron packs the lead no more than 1/8th inch and last the trimming iron

Use a joint runner for horizontal joints

On a practical test if you don't have the proper irons you fail


https://www.mephistotools.com/caulking-irons.htm <<< see

and



and

 

Breplum

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Best long term is to open more and replace with new no-hub cast iron. Three story requires all metal in Berkeley.
I still own all the lead caulking gear but isn't worth dealing with your steel pipe corrosion factor.
 

Breplum

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Wayne, CPC Drainage Materials Ch 7
701.1.2.2 [ HCD 1 & HCD 2] ABS and PVC installations are limited to not more than two stories of areas of residential accommodation
That is 2007.
 
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OP here: This joint has both rust and... on foggy mornings... wet rust. The rust appears limited to the outside of the pipe.

The poured lead solution won't work, not unless gravity inversion equipment is included.
That's a Y junction with the top of the Y pointed gravity DOWN.

The Fernco doughnut might be OK, but would have to be split to effect the repair without snapping pipes.



Probably expanding spray foam would do a pretty bang up good job: but someone might find a rule why it's not allowable. We're above the top fixture so it's just air, rain and cockroaches up there.


Fernco Donut.JPG
 
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Mr tee

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I would just try packing the lead you have in a bit more. There is a way to pour a new joint (that is how what you have got there) but it isn't something something that one without the right experience and tools should try to do.
 

Reach4

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If using a Fernco Donut, you would replace the galvanized pipe with plastic.

But yes, assuming there is actual moisture leaking, that caulking operation would seem worth a try. If there is just rust and not leaking, I would consider some kind of rust-treatment paint, such as POR-15 primer or some other material.
 

Sylvan

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I am shocked no one suggest lead wool (NOT legal) or Hercules propoxy
 

John Gayewski

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The pipe needs replaced. No reason to wait for it to leak. Drill the lead out and replace it with a donut. Easy peasy.
 
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I would just try packing the lead you have in a bit more. There is a way to pour a new joint (that is how what you have got there) but it isn't something something that one without the right experience and tools should try to do.
How is such a joint repacked "upside down" so to speak? I thought it involved pouring lead.
 
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I am shocked no one suggest lead wool (NOT legal) or Hercules propoxy
Is there a flexible epoxy, to account for future shifts in the building. A hard epoxy may crack over time, repeating the cycle. I assume that's why lead was used in the first place, it can accommodate shifts.
 

Reach4

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How is such a joint repacked "upside down" so to speak? I thought it involved pouring lead.
Caulking a leaded joint involves pounding on the lead with a "caulking iron" or other tool such as a big blunt screwdriver hit with a hammer.
 

John Gayewski

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See above: three story condo.
This is how modern cast iron is assembled. They/we don't poor lead anymore. It's a health hazzard. They use donuts. This thread is not useful to anyone. For an overthinker you seem to buzz right past the right answer and search for the one you want.
 
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Sylvan

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This is how modern cast iron is assembled. They/we don't poor lead anymore. It's a health hazzard. They use donuts. This thread is not useful to anyone. For an overthinker you seem to buzz right past the right answer and search for the one you want.
John I still pour lead joints as some of the older buildings have galvanized piping 4"- 6" and when installing a floor flange for example I do not have access below.

On roof drains I like to use lead as it is impervious to acid rain ,bird droppings and most importantly Rubber can crack over time as summer heats the drains to over 110 DEG F and in the winter they can go below freezing.

I had to install a drain on a set back and below was not an option so I had to use oakum and pour this joint
 

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