Bathtub drain and vent question

[Sergio D]

I am adding in a new tub/shower and I am dealing with a tight space. I have a drain below I can tie into and a vent in the wall I can connect to. I am wondering if both or at least 1 of my designs are allowed.

I believe option 1 makes it a wet vent, I'm just not sure if I'm allowed to use a sanitary tee this way? Also, the vent would tie into an existing horizontal vent that runs 3' up inside the wall. Are there any minimum distances that I need to be aware of?

I'm hoping option 1 is okay since option 2 is a bit crazy with a long vertical drop and the need to use elbows to avoid wall below.

 

[wwhitney]

Your vent has to rise vertically (which includes up to 45 degrees off plumb) from the takeoff point to a point at least 6" above the flood rim level of the fixture. Likewise two vents can be combined only at an elevation at least 6" above the flood rim levels of the associated fixtures.

So if it doesn't make your trap arm too long, you could put a san-tee upright under the current vent, run your trap arm across to it, and then from the bottom of the san-tee, turn the drain horizontal to run back to your existing drain location.

Cheers, Wayne

 

[Sponsor]

 

[Sergio D]

Thanks Wayne, I appreciate you taking the time to explain the code specifications dealing with vents. Unfortunately, there isn't room underneath the wall vent (hvac), but I think I can shift the tub to a spot where I have more room under the floor, I will just have to cut a notch in my floor joist which I was hoping to avoid.

 

[wwhitney]

Notching joists is definitely a last choice option, if you post some annotated pictures or dimensioned drawings of the framing, we might be able to help with an alternative.

Cheers, Wayne

 

[Sergio D]

I've attached the design I was hoping to achieve and what I think would work with a notch. I've also attached a few pictures. As you can see it is very cluttered, but to the left of the joist there is just the 3" toilet drain and 2 supply lines, much easier to work around, plus I can then vent through the alcove wall. I can't shift the tub further to the right since I need room for a sink and I've already cut the tub length down to 54".

Thanks for taking a look and please let me know if you have any other suggestions. This is a great forum!

Sergio

 

[wwhitney]

So the photos are of the existing condition, as you haven't made any changes yet to the framing or plumbing? Could you annotate the second photo with text over each pipe indicating what it is? Is that a 3" san-tee for the WC drain/vent, with a side entry for (?) ?

With the new location, it looks like the tub drain and overflow will be on opposite sides of the joist? So wouldn't that require notching the joist regardless? Waste and overflow assemblies are available with the joint drain under the tub drain or under the tub overflow. Have you picked out your tub yet?

Cheers, Wayne

 

[Sergio D]

Sorry, I did a terrible job explaining... I shouldn't have said "current". It's really design option 1, no notch... or design option 2, with notch.

I'm attaching my current floor plan along with my new one to give a better overview. I'm taking 1 bath and making into 2. Due to my hvac and then stairs underneath to the right of the hvac this is really the only layout that works.

I've already ordered the tub. I have seen the T waste connectors (joint drain under tub), but that wouldn't help me get to the left of the joist which is where I'll get more space and be able to run a vent through the alcove wall.

 

[wwhitney]

If I understand correctly, your first choice is to add a tub with the drain side against the stud wall shown in the first picture.

So why can't you tie your tub drain into the 3" stack below the san-tee with side inlet? Or if the pipe labeled "tub and sink" is 2", you could might be able to cut in a horizontal wye there.

Your vent could enter the wall through the plate to the right of the 3" vent, and rise up to that vent connection you have waiting.

Sorry if I'm not envisioning things properly.

Cheers, Wayne

 

[Sergio D]

Thanks Wayne, trust me, any confusion is only perpetuated by me. I think I'm started to piece together what is required. Would the attached work? Is it okay to have the 45 degree elbows on the vent there? And are the 22 degree elbows allowed at the tub drain? I might be able to squeeze in without the 22's, just figured I'd see if they are allowed.

If that does work, I would do what you suggested and tie into 3" stack below, there's just not enough space to tie into the "tub and sink" drain which is fine.

Thanks again!
Sergio

 

[wwhitney]

Yes to all three questions, at least as far as the portion depicted by your diagram.

I'm not convinced that the cleanout on the p-trap is a good idea; will it be accessible from below without removing the building finish? If not, just use a solvent weld p-trap without cleanout.

FWIW, they do make side outlet tub waste and overflow assemblies, but I think the pair of 22.5 degree bends would be preferable to a pair of 90s.

Cheers, Wayne

 

[Sergio D]

Awesome! Thanks so much Wayne, I truly appreciate your time and assistance. If you have a favorite charity, I'd love to make a donation in your name! You probably helped me save up to $1k.

I figure I may as well put in a cleanout. I have to remove building finish to put the wye into the main drain, so I thought I'd put in an access panel when I redo the wall there.

 

[wwhitney]

For my curiosity, is the pipe labeled "sink and tub" 1-1/2" or 2"? And that sink and tub are in addition to the tub we've been discussing?

Cheers, Wayne

 

[Sergio D]

It is a 2". I've attached an image that includes a 2" wye for perspective. Even pushed up against the joist I'd only have 2" in between connectors to fit a coupler on. The tub pipe will actually go away (was for old tub). Also, my plan is now to cap off the 2" connection to the main drain and actually route the sink drain down to connect with the new tub drain which then finally ties in below to the main stack. I'm already going to have to tie into the main drain since the 3 new fixtures for the second bathroom will need a place to connect. So I'll actually be adding in a double wye to the main drain.