Is this dwv config ok?

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Sydflash

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Humbly, I would like some opinions on whether this shower drain configuration is ok?

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Sydflash

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Sorry, I should elaborate on my concern... mind melted last night trying to figure out horizontal vents.

So, this is a shower in an addition that has remained unfinished for way too long.

The vent was in a shower wall but the studs bowed and twisted so bad I decided to take it out and build a new one.

So, as I am re-remodeling, the dimensions of the shower changed and the current drain location will not do - and I had it way to close to the wall anyhow.

I want to keep the same basic configuration but move the drain about 16" closer to where it heads to the basement.

In looking into if this was okay - I was worried about creating an "s" trap - I started to question the entire set up.

Every configuration I could find used a single vertical pipe that was both the vent and the drain, and the few sources discussing a set up like mine seemed to suggest it was not good but I couldn't find anything definitive.

So I am concerned there could be something wrong with having the vent on the other side of the drain - hoping that makes sense.

Thanks in advance for any help you can give me!
 
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hj

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WE would have to know the configuration of the shower, and the location of the walls to advise about the vent. i would NEVER use a "union joint" "P" trap under the floor.
 

Sydflash

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Basically there will be a wall where the vent goes up. I'd like to keep the vent where it is. I am limited to using the joist bay in the picture.

Also, I can't really move where the drain goes down into the wall below because of things in the basement that would be in the way.

Thanks for the advice on the P trap! I'll look into getting a solvent weld one. I do like the wiggle room of the union joint tho.
 

Cacher_Chick

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The vent needs to be downstream of the drain connection. No part of a dry vent can be horizontal below the fixture.
 

Sydflash

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Thanks Cacher! Can anyone point me to more info on this? What is used to determine the height of the fixture? Is it the height of the drain?
 

Sydflash

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Is the issue that something could get stuck in the dry portion of the vent? In that case would adding an accessible clean-out change things?
 

Sydflash

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kinda stuck here... anyone help? Did a lot of research and still don't get it, and the code is clear as mud. Anyone have the commentary on this type of horizontal dry drain?
 

Jadnashua

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I don't know enough to advise you further. Two things do come to mind though. On two inch pipe, your vent must be within five feet, and MA does not allow anyone but a licensed plumber to do this work, even in your own home. You can get into all sorts of hassles doing it yourself. The plumber would know what was required and how to do it .
 

Sydflash

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sorry, it's a summer home in NH, under 2009 IPC. Wish I could get a look at the commentary. Really bothers me that it's not available as a public resource.
 
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Sydflash

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Thanks Jadziedzic - I have the code but seems like the version with the commentary is much more enlightening, and unavailable.

Also seems like if the vent plugging up is the concern then a clean out would do the trick.

Does it matter that a blockage in the vent would only effect this drain as it is the only fixture on it?
 

Cool Blue Harley

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Alright. I'll try to help you. It's unbelievably easy.

First if all, the "invert" (interior bottom surface of a pipe) of the vent connection must be above the centerline of the drainage pipe to which it is connected. What this means is that your piping is all wrong.

Cut two inches upstream of the galvanized strap and throw all the piping away. Install a 2x1&1/2 PVC wye first, beginning where you cut. The branch of the wye, the 1&1/2 part, must be rolled up high, upper quadrant, because the vent is going to go over the top of the two inch drain pipe you're about to install.

Forget the vent for now. Install a short piece of two inch pipe into your wye to get you back to your original angle serving your p-trap created by using a two inch 45. Then a short piece of pipe over to your new glue joint adjustable p- trap, centered on your shower drain centerline.

Now your vent. Install an 1&1/2 street 45 into your wye branch aiming towards your vent wall. Your vent will cross over the top of your drain passing right by your shower drain riser and roll up in the same spot it is now or close.

One more thing. Your vent 90 rolling up in the wall, horizontal to vertical, must be an 1&1/2 LT 90. ( Long turn) because it is below flood rim.

Clear as mud. If anyone out there understands this and can help with an illustration...
 
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