# 2” Cast Iron through concrete



## djfremen (Feb 5, 2017)

Hey Gang,

I have a few casts going into an old laundry room I want to convert to a livable space. There are two inch cast iron (white pipes) and going to a lead and oakum bell inside the concrete. Thinking about trenching across the room if these actually go to a bigger 3" below... Anyone see this before? Why would they vent this way? Any advice how to explore this without breaking the cast bells?

thanks mucho,


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## daffysplumbing (Oct 16, 2017)

Every 2 inch drain eventually connects to a 3 inch or 4 inch sewer pipe. Every toilet has either a 3 or 4 inch sewer pipe. Locate the nearest toilet and determine what direction the pipe from the toilet runs to the city's sewer or septic system. When plumbers run cast-iron drains they always run the shortest distance to get out from underneath the house slab because cast-iron piping is expensive to run. Plumbers don't usually run sewer piping underneath foundations in a straight line because going diagonally takes more pipe. Then, when they get outside the foundation wall the plumbers will run the sewers diagonally to get to the connection at the property line or septic tank. 

It looks like the existing plumbing was modified after the initial installation, fixtures were relocated, or the job was bootlegged. It looks like there may have been a floor drain near the laundry sink and they is why there are 2 vent pipes.


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## djfremen (Feb 5, 2017)

daffysplumbing said:


> It looks like there may have been a floor drain near the laundry sink and they is why there are 2 vent pipes.



Thanks Daffys Plumbing. That’s great information. Indeed, right off camera there is the floor drain (hence the sloping concrete pour).

As far as workflow, would you recommend drilling pilot holes with a sds rotary hammer or scoring it with a carbide saw? It’s pretty fragile work for a jack hammer around vents, right?


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## daffysplumbing (Oct 16, 2017)

djfremen said:


> Thanks Daffys Plumbing. That’s great information. Indeed, right off camera there is the floor drain (hence the sloping concrete pour).
> 
> As far as workflow, would you recommend drilling pilot holes with a sds rotary hammer or scoring it with a carbide saw? It’s pretty fragile work for a jack hammer around vents, right?


If you are looking for the sewer pipe to install a larger pipe for a toilet I would not follow the 2 inch drain pipe. If that is a 2-story house there must be a sewer pipe going from a toilet into the concrete slab and that is the pipe I would try to locate and follow. For really old concrete, you we often use a 5 lb hammer or a sledge hammer. Looking at those old pipes it would probably be a blessing if you mistakenly break them and with all the plastic pipes and fittings today it is easy to replace drains. If I was keeping the house I would replace all the drains under the concrete slab all the way to outside the house.


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## djfremen (Feb 5, 2017)

Good advice. Thanks. There isn’t a toilet at the basement level unfortunately. The soil stack goes up 2.5 stories and likely exits the house by the 2” pipes (I hope). The backyard slopes so it can’t travel any other direct. I’ll post again when I find something.


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