[stubborn1]

I finally finished my demo work and framing for my new bathroom. The bathroom sits in a corner of the 1st floor of the house which has a full basement, but the foundation walls are about 18" thick cobblestone and the floor joists have about 3" of grout packed solid in the ends where they bear on the foundation at the rim joints. Getting piping vertical to the back wall which is the old exterior wall (pre-addition) is tricky, so I'm trying to only do it once hence the need for wet venting. See the attached diagram. After reading the code section for my area, this would appear to meet the intent of the code.

The 3" drain line will tie into the main stack for the house. The vent from this bathroom will go through the ceiling into the attic and tie into the existing main vent before it leaves the roof.

Can someone take a look at what I have drawn up here and let me know if you see any flaws?


Here's the code section I was reviewing in reference to horizontal wet venting.

(b) Horizontal wet vents. A drain from a lavatory or lavatories
which are either provided with individual vents or a common vent
may serve as the wet vent for not more than 2 bathtubs or showers
and not more than 2 water closets in accordance with subds. 1. to
7. No other fixtures may discharge into or be served by the wet
vent.
1. All of the fixtures shall be located in nonpublic bathroom
groups.
2. The lavatories and bathtubs or showers shall have a common
horizontal drain with the drain for the lavatories serving as
a wet vent for the bathtubs or showers.
3. Where 2 bathtubs or showers are served by the same wet
vent, their fixture drains shall connect independently to the common
horizontal drain downstream of the vertical drain serving the
lavatory or lavatories.
4. Where 2 bathtubs or showers and 2 water closets are served
by the same wet vent a relief vent shall be provided, unless the wet
vented horizontal drain connects to a drain stack with no other
drain connections located above the wet−vented horizontal drain.
The relief vent shall connect to the horizontal drain at a point
downstream of the fixture drains for the water closets and
upstream of any other fixture drain connections.
5. One or 2 water closets may connect to the common horizontal
drain with the drain from the lavatories and bathtubs or
showers also serving as a wet vent for the water closets. Where 2
water closets are served by the same wet vent, their fixture drains
shall connect independently to the common horizontal drain at the
same point.
6. The wet vent shall be at least 2
in diameter. No more than
4 drainage fixture units may discharge into a 2
diameter wet vent.
7. A branch vent shall connect immediately above the highest
fixture drain connection and shall be sized in accordance with sub.​

(14)

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[DannyT]

i would run directly to the toilet with the main run. just before the toilet wye off towards the shower, then another wye between the main run and the shower towards the back wall and everything will be vented. if you don't you would need another vent on the shower which you could run up the back wall and tie into the stack for the lav.

 

[Alan]

I agree with above : Horizontal wet venting is now legal here, but I have yet to see a situation where I would actually need to use it. :whistling2:

You can vent the toilet and the shower conventionally in the wall opposite the toilet, and branch off and run the lavatory drain independently. In this case, it is easier : Your drain will be behind a cabinet, so if you need to cheat a little bit out of the floor, it will be covered in the end by the toe kick.


Hope this helps (I can draw an iso if this is confusing)

 

[stubborn1]

Thanks for the feedback.

The reason I have the main run offset from the toilet is that there is an old window well opening in the foundation with its edge about 6" off of the center of the toilet. If I run directly underneath, i'll be into the stone foundation. It's not impossible, but I would need to chip away a few stones to make the clearance.

I think I understand the comment about running a wye off the 2" line to the shower. I can run that in the floor joists and up into the wall across the toilet for the shower vent and then tie into the lav vent above ceiling. In this scenario, would the vent off the 2" line to the shower count for venting the toilet? I guess I'm a little confused on that one.

 

[Alan]

Thanks for the feedback.

The reason I have the main run offset from the toilet is that there is an old window well opening in the foundation with its edge about 6" off of the center of the toilet. If I run directly underneath, i'll be into the stone foundation. It's not impossible, but I would need to chip away a few stones to make the clearance.

I think I understand the comment about running a wye off the 2" line to the shower. I can run that in the floor joists and up into the wall across the toilet for the shower vent and then tie into the lav vent above ceiling. In this scenario, would the vent off the 2" line to the shower count for venting the toilet? I guess I'm a little confused on that one.

I'll draw it up real quick for you... please hold.

 

[Alan]

Here ya go.

 

[Javiles]

Your Original Drawing is fine. if you can pipe the shower behind the toilet (up stream) even better the shorter the run from the toilet to the main the better. i have used this setup as long as i can remember simple clean and works well.

 

[DannyT]

your drawing in post 6 is fine with a vent on the shower line and the vent at the lav. the vent on the line to the toilet is not needed is not needed.