Installing a sink 20ft away from a drain pipe


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Old 09-22-17, 03:19 AM
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Installing a sink 20ft away from a drain pipe

I'd like to add a sink to my workroom on the second story of my house, however that room is 20 ft away from my bathroom. I was windexing how it would be possible to add a drain line that long? Would I have to open the floor to get it there (the room is on the opposite side of the house)? If so how would I support the weight 20 ft of 3in cast iron piping? Also do I need an additional vent for the sink to work? I read that a toilet has to be 5ft away from a vent, do the same principles apply to a sink? Thanks.
 
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Old 09-22-17, 05:26 AM
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Where are you located? Why would you use 3" cast iron for a sink drain? Then you mention a toilet. Is there more that you are not telling us?
 
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Old 09-22-17, 09:24 AM
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This is New York City. I just thought that was the code for a sink. I read that the drain has to be 3in. I also already opened the wall in my bathroom to see what I'm working with and the bathroom sink also has a cast iron drain. I'd much rather use pvc or some other metal if there is no difference, that's why I'm asking here. By the way the water flow in this sink will be moderate, it's industrial size so if it fills up and drains I'd assume it'd have the same water throughput as in a kitchen sink.
 
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Old 09-22-17, 11:07 AM
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Standard plumbing code (UPC) requires 2" drain pipe for a kitchen sink, 1.5" for a bathroom or utility sink. PVC is usually permissible and will need to be run with a 1/4" per foot slope downward until it gets to the main stack. You'll also need some type of vent. Some areas allow AAVs (Studor vents), while others require venting up through the roof.

Now, NYC is it's own animal with it's own codes that supercede standard UPC codes. Unfortunately, I'm not well versed in them, so can't really give you much information. It also likely will differ whether it's a single family residence, multiple family, or apartment building.

I found this online - but I can't confirm whether it's current.
https://www1.nyc.gov/site/buildings/...des.page#plumb

Hope this helps at least a bit!
 
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Old 09-22-17, 12:12 PM
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Thanks, a few questions about it though. How will I join the pvc with the cast iron pipe? If I run it under the floor it will meet the pipe 5 inches below so would I need to cut the cast steel one and how would I adjoin the plastic to metal? Secondly how do I support this long pvc pipe? Do I just tie it to joists in the floor like a suspension bridge? The venting is most crucial though, lets say I do use a AAV, can I just stick it anywhere? The sink is on a wall that interfaces the outside, so can I just drill a hole and shove the exhaust pipe out through the wall along with a studor cap on it, will there still be sewer smell coming through my window or do AAVs block that? Thanks.
 
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Old 09-22-17, 02:47 PM
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There are couplings for joining PVC to cast iron. Most are a rubber sleeve (Fernco) with a hose clamp at each end. No hub couplings have a metal sleeve on the outside for extra support. Both types are very easy to use.



 
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Old 09-22-17, 03:29 PM
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Zorfdt wrote:
Standard plumbing code (UPC) requires 2" drain pipe for a kitchen sink, 1.5" for a bathroom or utility sink.
Are you sure? Every kitchen sink I have seen is 1" and every vanity 1". True have seen on occasion 2" at the wall but I always thought that was either lack of knowledge or just what was on the truck. Much more often in kitchens though 1" is what I have seen.
 
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Old 09-22-17, 05:52 PM
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Thanks for the picture, I get the idea. Ok so do I need to cut into the cast iron put on some kind of Wye Bend and join in the pvc? But I'm not even sure how I would cut it, do I need to take a chunk of it out and replace with the wye, but how will the cut end and the wye seal up? Also when running that long of a distance there will be significant weight on the plastic from the water traveling how do I support the pipe? And as for the vent, what do I do about it? This can't be that exotic of a question I'm sure people install plumbing far from the vents all the time. Can anyone link to me a detailed followthrough or explain this thouroughly to me, I appreciate the bits and pieces you guys are giving me but I need something more concise.
 
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Old 09-22-17, 06:29 PM
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I would run a 2" pvc drain if your local code allows it. Must be supported every 4' or every change of direction. You can use plastic or metal plumbing strap that comes in a coil, blocks of would or I prefer plastic J hooks(pvc snaps in to the hook and the hook is nailed to joist).
Sink will drain thru 1 1/2" p-trap and can stay 1 1/2" pipe up to 42" before connecting to a 2x2x1 1/2 or a 2x 1 1/2"x 1 1/2" sanitary T. Vents typically have to terminate thru the roof but if an AAV is legal I would use it. I believe the aav just has to be installed in an accessible location above the flood rim of the sink. They are fine to use inside.
If you have a section of cast iron pipe about a foot and a half or two feet long you can cut out you'll have enough room for your pvc wye. For example if you are tying into 3" pipe use a 3x2 wye with a piece of 3"pvc glued in each end long enough to get a no hub coupler clamped on. Your overall length from one end of pvc pipe to the other is the length you cut out of the cast. I cut out a little extra for ease of installation. It's ok to cheat just a little.
 
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Old 09-22-17, 06:35 PM
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Also cast is hard to cut sometimes. You'll go thru a few sawzall blades or maybe you can rent a snapping tool made for this purpose
 
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Old 09-22-17, 07:37 PM
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Hey I just watched a video on bathroom installation and they mention something called wet venting, they just use a pipe thats larger than the water capaicity that is expected to be carried and the same pipe that supplies the waste channel also acts as a vent. In other words I'd use something like 4" in pipe for sink and it'd take care of the venting. Is that something I can do?
 
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Old 09-23-17, 04:17 AM
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Before you cut your cast iron riser make sure the pipe above is properly secured. You don't want to cut a section out and have the pipe above move or drop down.

Wet vents are not commonly used for sinks. For one thing it's much easier to install the proper size pipe and AAV. And, if you are going to run your drain line through the floor the size of pipe will be an issue to get the proper fall and still have it fit within the floor cavity. Don't forget you also have to be concerned about the floor joists. You are lucky if you can run down the length of a joist bay but if you have to cross multiple joists you also have to cut holes in the joists and you are limited in how big a hole you can make and where you can drill.
 
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Old 09-23-17, 09:06 AM
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@SDPlumber & Pilot Dane, all right that's solid info right there, thanks learned a lot from you guys. This is what I'm set for right now, run a vent vertically inside the wall behind the sink cutting it 6 in about the flood rim of the sink, capping it with an AAV. (This shouldn't be a problem right, that's it's drawing air from inside the wall, should be plenty in there?). Run the pvc of dimensions sdplumber mentioned with 1/4in/ft drop to main stack 25ft away, landing 6.25 in below starting point. Split the cast iron 2ft section with a dimond blade grinder and insert a long sweep wye, join it up with them hose clamps pictures of which pilot dane provided.

I sure hope this works. I think this is all possible, I'm just dead scared to starting opening the floors and perpendicular joists running all the way down, I don't even know what I'm going to do then.
 
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Old 09-23-17, 03:41 PM
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Do the math and see how much room your pipe with it's fall is going to need in the joist. What you DO NOT want to is start putting 2 1/2 - 3" holes in your joists in the wrong place and end up destroying that part of your house. I don't know how tall your joists are but that will determine how much room you have to work with and to make it more complicated you have to consider where your pipe will be passing through joists all along it's 20' run. You may be OK at one end and no good at the other.

 
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Old 09-23-17, 05:42 PM
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Siiick, I wasn't even aware this chart existed, can't tell you how many times I've crossed fingers and notched joists (probably in the wrong places). Thanks Pilot, that's an excellent reference. Still hoping I'd get lucky though and avoid the entire ordeal as drilling circular holes in 20 joists is not something I'm looking forward to.
 
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Old 09-24-17, 05:29 PM
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Standard plumbing code (UPC) requires 2" drain pipe for a kitchen sink, 1.5" for a bathroom or utility sink.
Are you sure? Every kitchen sink I have seen is 1" and every vanity 1". True have seen on occasion 2" at the wall but I always thought that was either lack of knowledge or just what was on the truck. Much more often in kitchens though 1" is what I have seen.
Ray,
My understanding is a recent code change (no idea what version) now requires a 2" pipe for kitchen sinks. The trap and trap arm may remain 1.5", but the drain needs to be 2". Maybe Lawrosa or SDPlumber can confirm or deny this.
 
 

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