Advice on connecting horizontal drain to Sewer main in crawl space

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stphn227

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Hello, i'm re-doing my upstairs shower in my 1960s home in Middle Tennessee. To my horror, when I got the old stuff out and the subfloor up, I discovered my drain is all 1 1/2 inch PVC all the way to the cast iron sewer pipe in the crawl space. I am aware that 2 inch is the new standard for showers, so I began the work of updated the PVC to 2 inch pipe.

I'm a rookie here trying to learn as much as I can, but I do know that whoever did this work previously didn't do it right. I'm attaching a rough sketch of what I believe is the proper design acceptable for today's code. My main question that I can't seem to find an answer to, when connecting the horizontal run in the crawl space to the main sewage line (the cast iron pipe), should a sanitary tee or long sweep 90 be used? My other thing is about the vent in the middle of the crawl space (this was here before. Not sure of it's purpose of if its needed, but wasn't about to remove it since I had no issues previously with drainage). That should be able to use a sanitary tee on its back since it's for venting purposes, yes? Or should that also be using a combo wye?

All the tees/wyes in the crawl space before I touched anything were all santary tees on their back. So either that was acceptable at some point, or whoever did this plumbing didn't really know what they were doing i'm guessing.

Thanks in advance for any advice.

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GReynolds929

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Floor 1 tub/shower needs a vent. The vent in the middle of the horizontal run is not needed and does nothing. I'm assuming it is, but the way it's drawn shows the tub trap and drain above the floor, it needs to be below the floor. The rest looks like it'll work to me.
 

royalflush001

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Long sweep 90° for sewer connection, not tee. Sanitary tee on its back for the vent, not combo wye. Local codes may differ, so check and slope the drain. Seal well and consider a plumber for the critical connection.
 

Tuttles Revenge

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On paper the upstairs looks good. The tub as mentioned above needs a vent in similar fashion so you don't create an S Trap.

The WYE going up to the upstairs with a cleanout is OK so long as its accessible.

The connection to the main building drain needs to be long sweep fittings... All Horizontal to Horizontal and Vertical to Horizontal fittings must be long sweep. Only where you are Horizontal to Vertical can you use a medium sweep fitting like a san tee at the sink.
 

stphn227

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Floor 1 tub/shower needs a vent. The vent in the middle of the horizontal run is not needed and does nothing. I'm assuming it is, but the way it's drawn shows the tub trap and drain above the floor, it needs to be below the floor. The rest looks like it'll work to me.

Thanks fellas for the replies.

Apologies for the rookie drawing. The little vertical lines at the bottom are my attempts are drawing the joists in the crawlspace, LOL.

Here's a picture of the P-trap for the tub in the crawl space. Again, this I haven't touched since I moved in the house 2 1/2 years ago.

So the vent/aav or whatever it is in the middle of the drawing in the crawl space does nothing? So I should be able to remove it then?

IMG_1102.jpg
 

stphn227

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Here are more pictures...this is how it was when I found it. I'm more surprised that the inspector didn't call any of these out at the time of purchase...these are all sanitary tees

IMG_1096 (1).jpg
IMG_1101 (1).jpg
 

Tuttles Revenge

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Most "Home Inspectors" for sales are usually only good at finding nitpicking nothing burgers unfortunately. They see pipe and no obvious water on the floor "all is good". I have dealt with a few that were good at their jobs and quite detailed.

The trap shown in the upper most pics is a classic example of and illegal "S-Trap" where your very likely to siphon the trap dry. And obviously all of those Tees on their backs are illegal. Likely the pipe they're connected to is undersized and hooked up to a steel pipe incorrectly too.
 

Jeff H Young

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Most "Home Inspectors" for sales are usually only good at finding nitpicking nothing burgers unfortunately. They see pipe and no obvious water on the floor "all is good". I have dealt with a few that were good at their jobs and quite detailed.

The trap shown in the upper most pics is a classic example of and illegal "S-Trap" where your very likely to siphon the trap dry. And obviously all of those Tees on their backs are illegal. Likely the pipe they're connected to is undersized and hooked up to a steel pipe incorrectly too.
A lot wrong there as you noted .
 
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