Potential Concrete Slab Leak

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JonW3

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Hey everyone,

I have a old home in San Francisco (104 years old). There is a waste pipe in the back that goes into the concrete and I just noticed that it is starting to leak. However, I can't exactly see where the leak is coming from.

It's in a precarious place, in between the foundation wall and a beam that helps support the bathroom above it. I tightened the fastners and it's still leaking.

I'm wondering if it's the Y pipe under the concrete. I want to get this fixed but I also don't want to spend an arm and a leg. Any ideas what could be wrong and how I can fix it?

Thanks everyone. 20200621_202528.jpg20200621_202519.jpg
 

Geofd

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Hey everyone,

I have a old home in San Francisco (104 years old). There is a waste pipe in the back that goes into the concrete and I just noticed that it is starting to leak. However, I can't exactly see where the leak is coming from.

It's in a precarious place, in between the foundation wall and a beam that helps support the bathroom above it. I tightened the fastners and it's still leaking.

I'm wondering if it's the Y pipe under the concrete. I want to get this fixed but I also don't want to spend an arm and a leg. Any ideas what could be wrong and how I can fix it?

Thanks everyone. View attachment 24638View attachment 24639
I think an option is having the pipe lined, I think your to close to that support to saw cut the floor
We use this me5hod at work when saw cutting /digging is not an option
 

frodo

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The leak looks to me is caused by the old cast iron pie and new cast iron connection

The old cast is dirty, was never cleaned when it was connected to the new pipe

dry the area, then, using a paper towel. start at connection and work your way down to the concrete
touching the pipe with the paper towel. If there is water present, it will wick onto the paper towel

remove the Band from the pipe and use black swan to seal the pipe to the band
 

frodo

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that is a drain? yes?
you might want to run the water through the drain as you are testing so it will leak


When you remove the coupling, just tell your family not to use any water. If they are hard headed then turn the water off
 

Jeff Handy

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The dark spray pattern on the wall and the floor, right in line with the no hub coupling that frodo mentioned, is a big clue.

That coupling likely has a bad seal.

Meanwhile, your pictures are shot too far to the left.
Take some more with the important areas properly centered.

And that gushing leak might indicate another problem.
That your drain line is partially clogged somewhere after it goes into the slab.
So you should have the older portion of the drain rodded out AND also camera checked.

104 year old drain probably has a collapsed area somewhere, or roots coming in, or some other choke point like a clay tile with a break that allows soil to push in and clog the pipe.
 

JonW3

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Oh man, now I'm nervous. I have a plumber coming to take a look on Tuesday. Sewer lateral in SF averages around $8K not including concrete pouring. I hope this is not the case.
 

Geofd

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Is an epoxy line a good cheap alternative?
Thank you for the response. Do I have to shut off the main water line before doing this?
[/QUOTE
If the issue is the exposed cast iron it’s not a big deal, like the above poster mentioned run the water in the fixture that connects to that line physically check while the water is running and if you can’t see all around the pipe get a inspection mirror
 

Geofd

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Not exactly cheap,check your exposed piping first
The company we use says there is a 50 warranty ,I have see the piping completely fail and the lining was still intact
Piping failed not only because of age but there was excavating and ground compactors working near
 

JonW3

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I can't see a leak from where the coupling is. I think it may be coming from the base of the cast iron, but I will dry it then put a dry paper towel around to see where it's coming from.
 

JonW3

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I'm starting to think it's the cast iron. I can now feel a leak from the cast iron area.

The coupling seems to be holding fine as I don't feel any water from there.

I hope it's just the wye cast iron part.

My water bill is the same amount, no backed up sinks, no water build up inside the house, no smells, etc.
 

breplum

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The section of cast iron is shot, both from age and strain.
To solve a leak like that, here is what we have done a few times.
A plumber is who would do this, not u!
1. Cut just above the place where the pipe enters the concrete.
2. Remove the old section of cast iron pipe.
3. Dry and wirebrush the inside of as much pipe as is practible. An extension on a drill with a spinning wirebrush will get in at least 10 ish inches.
3. Once fully cleaned, then a nice heavy layer of two part epoxy in a consistency that will allow lay-up and feathering. Let set.
Then add a no-hub cleanout right there using better matching fitting than a simple 4" no hub coupling.
Most plumbers will have a selection of various specialty couplings to work in cases of different o.d.
 

JonW3

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Thank yoy so much for the response. What do you estimate the cost for something like this? I'm in San Francisco, CA where it's expensive as hell, unfortunately. Thanks again

The section of cast iron is shot, both from age and strain.
To solve a leak like that, here is what we have done a few times.
A plumber is who would do this, not u!
1. Cut just above the place where the pipe enters the concrete.
2. Remove the old section of cast iron pipe.
3. Dry and wirebrush the inside of as much pipe as is practible. An extension on a drill with a spinning wirebrush will get in at least 10 ish inches.
3. Once fully cleaned, then a nice heavy layer of two part epoxy in a consistency that will allow lay-up and feathering. Let set.
Then add a no-hub cleanout right there using better matching fitting than a simple 4" no hub coupling.
Most plumbers will have a selection of various specialty couplings to work in cases of different o.d.
Than
 

breplum

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The work described is going to take two to three hours with an additional hour rounding up supplies.

A much better repair would break up the concrete to get at the few fittings involved and give you a better post base on that 4 x 4 while you are at it. For that it is about three to five hours of plumbing if you are lucky and that doesn't include saw cutting, concrete demo, replacement nor any carpentry.
 
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