Moving a sink waste line up

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Gary B

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Hi, I have a question that would seem to have an obvious answer but I am having trouble finding it.

I'm installing a new bathroom vanity in our downstairs half bath which is taller than the old one. This is the model:

https://www.homedepot.com/p/Home-De...Sienna-with-White-Basin-CA36P2COM-A/204205895

The problem is that the fixed bottom of the upper cabinet is exactly in line with where the waste line goes into the wall. I could cut away some of that bottom to make room, and that's a backup plan, but I don't like the idea of the P-trap hanging out in the open like that. Granted, most people wouldn't notice it, but I'LL KNOW IT'S THERE. You get me.

So, I'm thinking about cutting into the wall and moving the sanitary tee upward maybe 6 inches. It's got a typical vent pipe up/waste pipe down from there. My questions are three:
1. There's an upstairs bath pretty much right above, both installed by the builder 25 years ago when the house was built. My guess is that the vent is used as a waste pipe for the bath above, but I can't find anything specific that says whether or not that's allowed. Is it? Are there any gotchas I need to know?
2. I was trying to figure out how to attach the new tee into the line. Since vent and waste pipes cannot be moved, my best guess of how to splice it in is to cement the tee normally on the top and use a no-hub or flexible coupling on the drain side of the tee. Like this:
upload_2018-5-30_8-17-11.png


Is that the way to go? And should it be a no-hub or flexible coupling?
3. I know I can use a short hacksaw to cut the pipe in the wall. But I just bought one of those nifty oscillating tools and it seems like that might be just the tool for the job. Thoughts?

Thanks!
 

Reach4

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Since vent and waste pipes cannot be moved, my best guess of how to splice it in is to cement the tee normally on the top and use a no-hub or flexible coupling on the drain side of the tee.
Presuming that is galvanized pipe, you will need two no-hub (banded) couplings (above and below).

But I just bought one of those nifty oscillating tools and it seems like that might be just the tool for the job.
What will keep you from cutting through the wall on the other side? Galvanized is hard to cut. Have you established what pipe is there -- PVC or galvanized?

This would be a good job for a plumber, and you do the wall work yourself. The plumber will be much faster and less likely do do other damage.
 

Gary B

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Thanks for the info. Sorry about not saying - it's all PVC. I think you are right, I wouldn't tackle doing work on galvanized pipe myself. But I've done a fair amount of PVC work over the years, as well as soldering copper supply lines. Just haven't encountered this situation.
 

Reach4

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Much easier. You can cut PVC with a cable saw, and there is no chance of poking through the wall on the other side.

You will use two short segments of pipe to glue into a sanitary tee. If they had a sanitary tee with one end "spigot" you could use that. Those seem to be available in ABS but not PVC.
tees-wyes-c58112hd2112112-64_145.jpg


You will lubricate the pipe or coupling with dish soap. It is easier to put the metal band above or below where you are putting on the rubber part than to put it on later. It is possible to do later however if there is no slide clearance for some reason.

https://www.fernco.com/plumbing/shielded-couplings/proflex-couplings

Look for "PL" in the descriptions. That stands for plastic, including PVC.
 

Gary B

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That makes sense. Thanks for the info! Have not used a cable saw, but now that you mention it, I have seen them used. That sounds like the easiest way.
 

Reach4

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It is not permitted, but nobody is likely to catch you. Sometimes those are used when technically not permitted to work around a small misalignment.

Those have ribs too, I think. Once you have slid the shield out of the way, the black rubber is pretty similar to the un-banded units. You can stretch that rib over the pipe. A flat blade screwdriver can help serve as a little shoehorn to assist. Use the liquid detergent.

Clean the outer edges after the cuts. Maybe make a tiny bevel even. Sandpaper would be a good tool. A drywall sanding screen would be good if you have that handy.

When you get in there, you may find the drain and vent pipes are different sizes. So know that before you get your parts.
 
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Gary B

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Got it. I'll go for the shielded one. I see where the liquid soap would come in handy there, having pulled cable through conduit.

I would really like to be more educated. When I was doing electrical work around the house, I spent a lot of quality time with a book that really explained the ins and outs of the NEC. Is there a similar book for the plumbing code? I just looked through the VA plumbing code and it's hard to find the answers to questions like this. The closest thing I can find to an answer is a reference without explication to a bunch of standards including the one that I think applies (CSA B602, available in PDF form for the low, low price of $206).
 

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https://www2.iccsafe.org/states/virginia/plumbing/plumbing_frameset.html seems free but not so readable... as is normal for codes.

https://up.codes/viewer/virginia/va-plumbing-code-2012 says code is based on IPC. IPC (International Plumbing Code) is less restrictive in general than most. For example, IPC usually allows longer trap arms. Works fine. There are amendments. When you read that section xx of the code is removed/deleted for a county/state, that means they don't allow whatever that section covers.

http://www.co.lincoln.or.us/sites/d..._-_helpful_hints_residential_construction.pdf has some easy overview stuff. It is from Oregon. The western US tends to use ABS DWV piping and much of the rest of the US tends to use PVC. For many purposes they are interchangeable, but are usually not permitted to be glued to each other. Use what is common locally, and for you, that is PVC.
 

Asktom

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You can fold back the rubber on the top and bottom bands, push in the new tee and pipe then snap the rubber down.
 
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