Master Bath Vent

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JCConst

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Hello,

I am installing a master bath on a second story floor. Got a little excited and started glueing things together then started questioning where to vent the fixtures. You can see where the vanity will run. There will be a wall framed there and and easy route for a dry vent up through it. However the toilet and shower raise an issue. The f/j are 2x8. I already cut through the top of one f/j and the 2" pipe is above plane just a bit. The wye set up is too tall for the f/j on the back of the toilet. I am about to run a horizontal 2" wet vent to the exterior wall for the toilet and one off the short pipe between the shower trap / 3" branch.

Any thoughts?

Thank you!

IMG_0488.jpg
 
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wwhitney

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With 2x8 joists it's going to be hard to get everything to fit. Where is the 3" drain going off the right of the picture?

The notch you made for the shower drain is bigger than allowed, and it will require repair or reinforcement. It's also too high to be useful for wet venting the shower.

The lav drain can wet vent the WC (and could wet vent the shower). But the lav drain will need to be 1-1/2" (as will its vent), and so you'll want to drill a 2" hole minimum for it. That hole needs to be at least 2" from the top and bottom of the joists. So if the joists are 7.25" tall, you have at most the central 3.25" of joist to use, and a 2" hole can fall at most 1.25". That means your lav drain can only run 5' at 1/4" per foot fall (possible more as there are joist bays at the beginning and end).

Those considerations will dictate the height of your WC drain. And then by the time the WC drain reaches the shower area, I expect it will be too low to allow the shower drain to connect to it (the hole would be closer than 2" to the bottom of the joist) and too low to keep the shower trap above the bottom of the joist. That will preclude wet venting the shower from the lav.

So the shower will likely require a conventional dry vent takeoff. If the right of the picture is a wall with a wall stacked below, and the 3" WC drain turns down into that wall, you can put a san-tee under the wall, with the dry vent rising into the wall above. The drain can join the WC drain on the vertical in the wall below.

Cheers, Wayne
 
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JCConst

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With 2x8 joists it's going to be hard to get everything to fit. Where is the 3" drain going off the right of the picture?

The notch you made for the shower drain is bigger than allowed, and it will require repair or reinforcement. It's also too high to be useful for wet venting the shower.

The lav drain can wet vent the WC (and could wet vent the shower). But the lav drain will need to be 1-1/2" (as will its vent), and so you'll want to drill a 2" hole minimum for it. That hole needs to be at least 2" from the top and bottom of the joists. So if the joists are 7.25" tall, you have at most the central 3.25" of joist to use, and a 2" hole can fall at most 1.25". That means your lav drain can only fall 5' at 1-1/4" per foot (possible more as there are joist bays at the beginning and end).

Those considerations will dictate the height of your WC drain. And then by the time the WC drain reaches the shower area, I expect it will be too low to all the shower drain to connect to it (the hole would be closer than 2" to the bottom of the joist) and too low to keep the shower trap above the bottom of the joist. That will preclude wet venting the shower from the lav.

So the shower will likely require a conventional dry vent takeoff. If the right of the picture is a wall with a wall stacked below, and the 3" WC drain turns down into that wall, you can put a san-tee under the wall, with the dry vent rising into the wall above. The drain can join the WC drain on the vertical in the wall below.

Cheers, Wayne

A few inches passed the vanity fitting (to the right) Is the middle of the 2x8. Which is about 5’ from the toilet and about 5’ from the shower. I can’t come off the top but at a horizontal with 1/4” pitch can be done.

The branch line drops with a sweep 90 through the walls. I definitely do not plan on getting into the lower walls.

I appreciate the reply Wayne.
 

wwhitney

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A few inches passed the vanity fitting (to the right) Is the middle of the 2x8. Which is about 5’ from the toilet and about 5’ from the shower.
So the toilet-WC distance is 10' (big bathroom) and the 3x3x1-1/2 combo is about half way in between? I think you're going to need that combo to be lower, so that the bottom of the combo inlet is only about 2" above the bottom of the joist, so that your vanity line can comply with the drilling limitations.

The branch line drops with a sweep 90 through the walls. I definitely do not plan on getting into the lower walls.
Where the branch turns from horizontal to vertical, it can be a quarter bend instead of a long sweep 90, which could help you drop the branch line if necessary.

Right now the shower is not properly vented (and does it connect to the 3" branch with a combo as required?). I'm not sure if you're going to be able to find a venting solution for the shower without opening the lower walls. To wet vent the shower, you'd need the combo where it joins the branch line to be horizontal, not rolled up like you have it. The "trap weir rule" limits the drop from the trap to the vent connection (the branch line if wet venting) to one pipe diameter.

Cheers, Wayne
 

JCConst

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So the toilet-WC distance is 10' (big bathroom) and the 3x3x1-1/2 combo is about half way in between? I think you're going to need that combo to be lower, so that the bottom of the combo inlet is only about 2" above the bottom of the joist, so that your vanity line can comply with the drilling limitations.


Where the branch turns from horizontal to vertical, it can be a quarter bend instead of a long sweep 90, which could help you drop the branch line if necessary.

Right now the shower is not properly vented (and does it connect to the 3" branch with a combo as required?). I'm not sure if you're going to be able to find a venting solution for the shower without opening the lower walls. To wet vent the shower, you'd need the combo where it joins the branch line to be horizontal, not rolled up like you have it. The "trap weir rule" limits the drop from the trap to the vent connection (the branch line if wet venting) to one pipe diameter.

Cheers, Wayne
Here is some better photos. You are correct about the trap weir. I am measuring further up the branch then what I was thinking. At this point I will either vent the WC mid branch and the shower as shown in the photo. I value your response and thank you! I have included some photos of the rooms below. Not that I am trying to convince myself but I just finished those rooms not long back. The amount of work ahead is convincing enough..
 

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wwhitney

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I don't think you have any questions in there, but I'd just like to comment that it's best not to assume the ceiling board is level--you want to check that before using it as a reference.

Cheers, Wayne
 

JCConst

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How about this sanitary tee I used into the horizontal drain. I don't think I had any other option to make this work! The first one is the wet vent. The shower does have the WC and the sink up line. Maybe clean any up hill splash from the shower?

tempImageseeSUA.png
 
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Terry

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You can't have a horizontal santee for waste or venting there.

You could have had a 3x2 wye, street 45 and then a long turn 90. Or I suppose a combo to replace the 90 so that one end is for the vent. Not sure I could get that passed either, but it would be way better than two santee fittings with no sweep on them.
 

JCConst

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I appreciate the response!

Is the “can’t” because of a potential clog?

I literally had a combo sitting in front of me, I planned on using it. Some how the santee took its place.

I don’t know how it would be changed at this point. A repair fitting on the branch and saw out what is there? I tried a repair fitting a while back. Once I primed it and slid it on and up the pipe it wouldn’t slide back. The primer caused too much friction. The only way it would slide was w/o primer..

I don’t know any other way to vent the shower for what is available in this exact space. I would rather have a horizontal vent then none at all.
 

wwhitney

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As I commented earlier, if you can't lower the shower trap because it would show through the ceiling and you don't want to deal with that, you need to send the shower trap arm towards the wall to a san-tee for venting, and then join the shower drain to the other drains on the vertical in the wall below. That will also let you repair the excessively large notch you have in the top of your 2x8 joist.

Cheers, Wayne
 

Terry

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Is the “can’t” because of a potential clog?

A santee on the horizontal doesn't guide water downhill properly. Snaking those fittings are hard too.
What you have there with the 2x8 floor joists is a hard one to do right. Sometimes the soffits in the corners of the ceiling below are what hides pipes crossing floor joists below. Often, you can wet vent a shower and toilet with a lav. Having to bring it up kind of defeats that, making venting more difficult.
 
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