single to double vanity drain with stack on far left side

[tpittman]

Doing a bathroom remodel where I am changing to a double sink vanity. After looking around a bit I have seen how to handle the drains with venting when the stack is in the same wall. Although I am a bit unsure how to address my situation where the stack is in the adjacent wall. This is the main stack for the whole house as both bathrooms and kitchen come together.

I wanted to see if my suggested drawing seemed appropriate and how to handle getting into the corner to properly install the venting, or if there was a better more efficient way.

Behind wall A is the second bathroom, behind wall B is the kitchen. Pipe #1 is the drain from the kitchen sink, pipe 2 captures both bathroom vanities, and #3 is the drain for the dishwasher. Tried to draw my thoughts based on what I have seen on other forum posts but the corner is whats throwing me off on how to address it.

Any thoughts and insights would be wonderful!

 

[Tuttles Revenge]

You've got a tricky one. But I can't make heads or tails out of that code. Their section on sanitary drainage doesn't really specify much as far as how to or how not to install drainage.

Is the stack a vent above #1-Kitchen? or does it serve as a drain for fixtures on a floor above?

#2, A - Second bath sink appears to be draining with a san tee on its side into the same drain as B which has no individual vent which we're trying to remedy now. A should be vented and drained with drainage pattern fittings which in this case is a wye. How it gets vented?

Sizing of the drains needs to be considered as well on Table 710.1(1) . Lavatories are considered 1DFU (chart 709.1) and 1.5" drains at 1/4" slope can carry 3DFU horizontally. (*wildly different than UPC code*)

I just don't know if the sink drain you're proposing can wye off on the horizontal as you have drawn, which is OK in the IPC, but not in UPC.

I'm not sure I've conclusively answered anything here.. but wanting to start getting this figured out.

 

[Sponsor]

 

[tpittman]

Is the stack a vent above #1-Kitchen? or does it serve as a drain for fixtures on a floor above?

Yes it is a vent above #1-Kitchen, single story home with a basement.

#2, A - Second bath sink appears to be draining with a san tee on its side into the same drain as B which has no individual vent which we're trying to remedy now. A should be vented and drained with drainage pattern fittings which in this case is a wye. How it gets vented?

That is correct, right on the other side of A is the second bath vanity. I plan to remodel that in the future as I noticed it also did not look right, is it being a san tee an issue I should address now or will it be fine for the future untiil I remodel that other bathroom?

Thanks for your insight so far.

 

[Jeff H Young]

I dont know your code but assuming the photo is current plumbing adding the lav and the vent as proposed would be better than what you have now. We have a strictor code than most of the east it most likely flies there but like I said its better than it was before, which unfortuanately makes no differance to an inspector. if not inspected you shoulod have no function issue if you didnt before

 

[Tuttles Revenge]

It looks like there is enough room to get a wye installed for the A bathroom sink in that 2x6 wall, maybe with some creative offsetting of the kit sink drain. Or a stub into the basin with an AAV which is allowed in the Detroit code(905.1).

In detroit code 911.1 Individual vent as Common Vent: I think that a single vent may vent 2 fixtures. But because the fixture drains are at the same level I believe that the vent must be where the 2 drains meet together, like a vertically installed fixture cross fitting.

The IPC code would allow the trap arm of one lav to serve as the trap arm of 2 lav fixtures (not something we do in the UPC so I'm not really up to par on that)

Link to Detroit code via UpCodes.

Chapter 9 Vents: Vents, Detroit City Plumbing Code | UpCodes

UpCodes offers a consolidated resource of construction and building code grouped by jurisdiction

up.codes

 

[John Gayewski]

For the bit about the corner. You have to remove the wood by cutting a channel in the studs. If this is a partition wall it's fine, but a bearing wall needs to be reinforced properly after you remove the wood material needed to run the piping.

I would say your legal under circut venting standards.

 

[wwhitney]

In detroit code 911.1 Individual vent as Common Vent: I think that a single vent may vent 2 fixtures. But because the fixture drains are at the same level I believe that the vent must be where the 2 drains meet together, like a vertically installed fixture cross fitting.

Per your link, 911.2 in Detroit is unamended from the IPC, and allows the common vent to be "at the interconnection of the fixture drains or downstream of the interconnection."

Cheers, Wayne

 

[Jeff H Young]

put 3 cheater vents on and you dont even need to unravel the code , or need to hack the structure .
so I didnt catch the 2x 1 1/2 x 1 1/2 santee on its side for lav.
just noticed that at the main stack what I think is a kitchen sink "3" roughed in That should be a 4x4x1 1/2 san tee (unless its revented ), we would never build that way some really slack inspectors around the country and then there are the hard asses
These IPC codes confuse me so its a common vent , circuit vent what about horrizontal wet vet ?

 

[Jeff H Young]

Per your link, 911.2 in Detroit is unamended from the IPC, and allows the common vent to be "at the interconnection of the fixture drains or downstream of the interconnection."

Cheers, Wayne

Wayne, So Im just wondering if that means the way he drew over the photo its legal or illegal? aside from the excisting lav santee thats on its side also wondering if a single aav at the end would be a go in Detroit code

 

[wwhitney]

Wayne, So Im just wondering if that means the way he drew over the photo its legal or illegal?

If you're referring to the last photo in the OP, my take on it, assuming the top of the stack shown is a full size dry vent through the roof (no fixtures above or reduction in size):

The kitchen sink (connection #1) is dry vented by the stack. The right hand lav is dry vented, which is revented to the stack (assuming the horizontal vent is at least 6" above the lav flood rim). That dry vented lav wet vents both the proposed new left hand lav and the lav in the other bathroom. So connection #2 does not need to be a connection that is considered to provide a vent.

As for stack connection number 3, however, we'd have to look at IPC 913 Waste Stack Venting or IPC 918 Single Stack Venting in order for it to be seen as providing a vent for the dishwasher. I'm less familiar with those sections, but I think IPC 918 allows the stack to serve as the vent for connection #3. Not sure on IPC 913, it has the language "Fixture drains shall connect separately to the waste stack," which I think means that because connection #2 has multiple fixtures, the waste stack configuration shown is outside the scope of IPC 913.

Cheers, Wayne

 

[Jeff H Young]

If you're referring to the last photo in the OP, my take on it, assuming the top of the stack shown is a full size dry vent through the roof (no fixtures above or reduction in size):

The kitchen sink (connection #1) is dry vented by the stack. The right hand lav is dry vented, which is revented to the stack (assuming the horizontal vent is at least 6" above the lav flood rim). That dry vented lav wet vents both the proposed new left hand lav and the lav in the other bathroom. So connection #2 does not need to be a connection that is considered to provide a vent.

As for stack connection number 3, however, we'd have to look at IPC 913 Waste Stack Venting or IPC 918 Single Stack Venting in order for it to be seen as providing a vent for the dishwasher. I'm less familiar with those sections, but I think IPC 918 allows the stack to serve as the vent for connection #3. Not sure on IPC 913, it has the language "Fixture drains shall connect separately to the waste stack," which I think means that because connection #2 has multiple fixtures, the waste stack configuration shown is outside the scope of IPC 913.

Cheers, Wayne

I was mainly talking about connection number 2 aside from the length of trap arm might be an issue. was it legal befor or does it even need a dry vent added because a lav was added . I wouldnt do that here in UPC country but Id be somewhat comfortable with it funtion wise with that dry vent added without it not so much but admitedly that setup I wouldnt feel that confident as far as inspection thats why I asked

 

[tpittman]

I appreciate all the posts but I think I am still unsure of the best approach to add venting into this scenario and am getting a tad lost sifting through the codes for venting.

To clear up some past points that were pointed out, the stack seen vents directly out through the roof to atmosphere with no other fixtures that tie in above what is pictured.

I have not noticed any issues prior with the current setup but I don't know if I can honestly say I would know what issues would come from an improperly vented system. I believe it would suck out the traps for the different fixtures causing a sewer smell, but never really noticed anything prior.

From more searching I have done on solutions, I have seen the suggestion to add in AAVs if its not practical to tie in to the stack creating a proper vent, is that something that would be acceptable? I believe its preferable to tie into the stack since it does seem possible. Can AAVs cause potential problems in the future? Would not be opposed to use them if it makes the most sense to do so here.

For my initial thought of cutting out that corner and running venting to tie into the stack for this current bathroom, does that seem to be a good solution? Wall B is a load bearing wall and would need to added to add in order to reinforce the structure back, my thought would be adding a bracket of some sort.

Again I appreciate everyone's thoughts so far!

 

[Jeff H Young]

I appreciate all the posts but I think I am still unsure of the best approach to add venting into this scenario and am getting a tad lost sifting through the codes for venting.

To clear up some past points that were pointed out, the stack seen vents directly out through the roof to atmosphere with no other fixtures that tie in above what is pictured.

I have not noticed any issues prior with the current setup but I don't know if I can honestly say I would know what issues would come from an improperly vented system. I believe it would suck out the traps for the different fixtures causing a sewer smell, but never really noticed anything prior.

From more searching I have done on solutions, I have seen the suggestion to add in AAVs if its not practical to tie in to the stack creating a proper vent, is that something that would be acceptable? I believe its preferable to tie into the stack since it does seem possible. Can AAVs cause potential problems in the future? Would not be opposed to use them if it makes the most sense to do so here.

For my initial thought of cutting out that corner and running venting to tie into the stack for this current bathroom, does that seem to be a good solution? Wall B is a load bearing wall and would need to added to add in order to reinforce the structure back, my thought would be adding a bracket of some sort.

Again I appreciate everyone's thoughts so far!

the way it was befor didnt have a revent adding the other lav Im not sure changes things , the santee on its side im sure is wrong (but its just a lav and a small snake could go in either at that lav or another and clear the line ) but why not fix it?
I dont work in your code and didnt look all this up I guess wayne did and I apreciate that but I dont quite follow his opinion on the Detroit code and if your revent plan meets code and just becaiuse it was inspected befor dosent mean they looked at it closely
If the revent would be ok I see no reason an aav on the furthest upstream lav wouldnt meet code as well