Need to raise drainpipes for hanging vanity

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Reach4

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Hmm, I thought the purpose of the street elbow was to a avoid using a short piece of pipe? The existing pipe goes right into one end of the shielded coupling, then the street elbow goes into the other? Now I am getting confused, but I think if I buy a bunch of fittings I can probably just piece it together
If you use a shielded coupler, the coupler has to grab something that is pipe-sized on each side. That thing on the right would be the pipe, cut to at least just over an inch long, out of the stud.

On the left, it would either be
  • the spigot output of a street bend
  • a piece of pipe sticking out of a hub-hub bend by a little over an inch.

Picture yourself putting it together. Hook up the lower right. Hook up the vent pipe up top. Which of those things would you do first, and which would you do last, as you picture the process?

Now it could well be that you could just glue a hub to the piece of pipe near the stud. But you have to get it right the first time. You also have to figure out how you make the hookup to the vent pipe. If you were a plumber, you could probably get it right the first time. Or you use a shielded coupler, where you will have the ability to rotate into position, take it back out, re-do something, and put it back. What redo? For example, maybe file a pipe 1/16 inch shorter to make things line up.

I would probably plan to use two shielded couplings -- lower right, and up at the vent, both. You may be able to glue one. You probably cannot glue both.

How far is it from the centerline of the vertical vent pipe to the stud on the right? That can help identify your options.
 
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So, I dry fitted the pieces together. Did not use the shielded coupling on the pipe sticking out of the stud because I would have to flip the street elbow over and it would raise the height of the final drain pipe an extra inch that is a little too much.

I'll use the shielded coupling on top. Is this design valid?
 

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So, I dry fitted the pieces together. Did not use the shielded coupling on the pipe sticking out of the stud because I would have to flip the street elbow over and it would raise the height of the final drain pipe an extra inch that is a little too much.

I'll use the shielded coupling on top. Is this design valid?
And I noticed the sanitary tee is upside down. I'll fix that before glueing it all together.
 

wwhitney

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Do you need the sanitary tee moved to the right like that? You could eliminate both elbows by adding a pipe segment to the outlet of the long turn 90. Or if you really do need it moved to the right slightly, two 45s (one possibly street) would be better.

BTW, the only reason for the rubber coupling is to aid in assembly. If you can figure out an assembly order where you can place the last fitting and glue both its connections at once, you can omit the rubber coupling.

Cheers, Wayne
 

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Do you need the sanitary tee moved to the right like that? You could eliminate both elbows by adding a pipe segment to the outlet of the long turn 90. Or if you really do need it moved to the right slightly, two 45s (one possibly street) would be better.

BTW, the only reason for the rubber coupling is to aid in assembly. If you can figure out an assembly order where you can place the last fitting and glue both its connections at once, you can omit the rubber coupling.

Cheers, Wayne
Yes it needs to be to the right otherwise the "U" shape void where the vanity drawer is will not align with the drain pipe. All of this work is to center the plumbing into a small 10" x 10" space.
 

Reach4

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I'll use the shielded coupling on top. Is this design valid?
No. You cannot go horizontal with the vent below 6 inches above the flood level (rim) of the sink.

If you went to two 45s instead of two 90s, then you would be OK; 45 off of vertical is considered vertical. However you would need to connect the vent higher for that to work.
 

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No. You cannot go horizontal with the vent below 6 inches above the flood level (rim) of the sink.

If you went to two 45s instead of two 90s, then you would be OK; 45 off of vertical is considered vertical. However you would need to connect the vent higher for that to work.

What if I extend the vertical run above the sanitary? I can go as far vertical as I need, I would just remove more drywall.

The santee is upside down.
 

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Reach4

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What if I extend the vertical run above the sanitary? I can go as far vertical as I need, I would just remove more drywall.
That works with two 90s high enough, or two 45s.

Here is another alternative. Put the trap adapter right on the santee, so no elbow feeding the trap arm to the santee.

Vent above the santee can come in at 45 or vertical, or in between.
 

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wwhitney

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If you need the trap arm coming out of the wall to be to the right from previously, you can turn the san-tee so the opening is facing out the wall. You also have the option of turning it 45 degrees and use a 45 on the inlet instead of a 90. Making a mark on the wall where you need the trap arm to come out and showing us the photo would help us advise you.

If you want to keep your current pattern, you need to raise the double vent 90s to be at least 6" above the sink flood rim. But one of the other solutions would be more robust.

Cheers, Wayne
 

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If you need the trap arm coming out of the wall to be to the right from previously, you can turn the san-tee so the opening is facing out the wall. You also have the option of turning it 45 degrees and use a 45 on the inlet instead of a 90. Making a mark on the wall where you need the trap arm to come out and showing us the photo would help us advise you.

If you want to keep your current pattern, you need to raise the double vent 90s to be at least 6" above the sink flood rim. But one of the other solutions would be more robust.

Cheers, Wayne
I forgot that I can just turn the santee to face outward! I am going to dry fit that and also open up the wall to raise for elbows for the vent since I don't wan't to go out and buy 45's. I'll give it a shot today after work. Thanks everyone!
 

Jadnashua

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Before you end up cutting a bunch of pipe, keep in mind that it usually doesn't work dry fitting pvc pipe. The fittings are slightly tapered, and when you add the cement, the pipe will go into the fitting further because it literally melts and lubricates things, then, when the solvent evaporates, it is solvent welded together. You have to take careful measurements.
 
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