Master Bath Renovation

[Arnav]

Hi All,

Background:
- South Florida 3 story town home. 18 years old.
- I am renovating the master bath on the 3rd floor.
- All the copper pipes, shower valve, and some of the DWV pipes are on exterior cinderblock walls.
- I have access from below to the toilet and double lavs pipes.
- I don't have access from below to the shower or tub drains. They are above a porch so you would need to break through the stucco. In addition, first you have the actual subfloor/underlayment (0.75" + 0.75") and then a raised platform also with two ply layers (0.75" + 0.75"). See pics.

My first querstion is about the current venting and whether it is correct.
- The shower drain is about 30' from the main vent stack that goes to the roof.
- Would be nice if there was a separate vent to the roof for this bathroom but there isn't. Getting the HOA to approve another vent to the roof will be a major pain.
- There is an AAV for the double lavs and that's it.

I am dubious of anything the builder has done since most of it was not to code but thinking about the venting, seems like perhaps it is ok? My logic as as follows:
- The shower drain is at the end of the line, so no venting is required.
- The tub has an overflow so no additional vent is required.
- The AAV while not ideal as a vent, is sufficient for the two lavs.

There was no bad smell in the bathroom previously.

What do you think?

 

[Reach4]

My logic as as follows:
- The shower drain is at the end of the line, so no venting is required.
- The tub has an overflow so no additional vent is required.

Those two are not right.

You need to vent the shower and tub before the output of the traps stops turn down. I suspect you can bring the lavatory drain over above the floor, then down, and join between the shower and tub traps. That would wet vent those traps.

- The AAV while not ideal as a vent, is sufficient for the two lavs.

True, but the path from the top of the double sanitary tee to the AAV should stay no more than 45 degrees off of plumb. The way you have it would probably work but not meet the rules.

 

[Sponsor]

 

[Jeff H Young]

A tub overflow has nothing to do with and is not a vent doesn't help with venting either. tub and shower is either non vented or improperly vented . But I'm sure with all the work you are doing shouldn't be too hard to come up with better venting

 

[Arnav]

Thank you very much for the quick replies. For some reason I didn't get a notification. Usually I do. Maybe I forgot to check an option when starting the thread?
It does say that I am watching it.

I was trying to wrap my head around what wet venting is. Where I am stuck is trying to convince myself that it is not already wet venting. Apologies, I don't want to be argumentative, I know you said the builder did it wrong but what I didn't show you is that the tub/shower are connected to the lavs under the floor. Please see the attached pics (in conjunction to the previously uploaded ones).

2" pipe everywhere except the 1.5" from the tee to the lavs

Isn't that in fact wet venting?

Many thanks for the help

 

[Reach4]

Isn't that in fact wet venting?

How is this new picture related to the first two?

 

[Arnav]

I know. its confusing. I wish I had a wide enough angle. If it is still confusing, I'll stitch multiple pics together.
(1) donates the pipes going to the tub/shower
(2) donates the lavs connection

 

[Jeff H Young]

Sorry arnav, no it doesn't comply actually the added pic doesn't help .
What exactly are you doing? just putting everything back how it was is what you were hoping for? getting a vent coming off between tub and shower would be a tremendous help . trying to come up with a legal solution

 

[Reach4]

2 inch shower pipe has to be vented within 8 ft of the P-trap U. That can be a vertical dry vent, or it can be a wet vent. Venting must be done before the pipe goes non-horizontal.

Attached sketch shows adding a dry vent for the shower, which then wet-vents the tub. The dry vent must stay within 45 degrees of plumb.

 

[Arnav]

trying to come up with a legal solution

Of course. That is why I am here! Thanks for the time. I take pride in leaving it better than how I found it ...

Here is a last ditch effort to show what is going on there. I was able to fit most of it in a single frame.

The scope of work is:
- Replace shower with a new shower
- Replace corner tub with free standing tub
- Replace 80" vanity with 60" vanity (so the DWV, supply lines, and AAV will be shifted to the left).

Also, is this what you are suggesting? Please see last pic.

 

[Arnav]

Thanks Reach. I posted a few minutes after you, missing your post.

"vent" in your example can be an AAV right?

I think I get it.

Where your vent comes out there will be a 2 x 6 instead of the metal stud the builder have used (!) which would be nice to avoid notching.
I'll try and counter propose for your review a layout with venting through the left or right walls where it is easier to accommodate the thickness of the vent.

 

[Reach4]

"vent" in your example can be an AAV right?

Yes. It needs to be up 4 inches, and does not have to be higher than the flood rim of the tub. They make boxes for AAVs with louvers to pass air and allow access to replace the AAV.

Your wide 3 may be acceptable EXCEPT that you need to connect below the double fixture fitting instead of above. Then the drain into the floor under the lavatories does not get used. The wet vent carries the drainage over to the shower trap arm. If you tee off above the double fixture fitting, it is a dry vent that cannot go horizontal, plus you can't share a vent horizontally below 6 inches above the flood level of the lavatory. Wet vents can go horizontal.

All vertical to horizontal 90s are long sweep.

 

[Jeff H Young]

Arnav, ok good I just wasn't sure basically everything going back as is with some adjustment likely on the precise location of traps. Reach 4 came up with good solution , I thought of similar but didn't know if access panel in wall works out . I suppose a panel in ceiling might be an idea and less noticeable. We in my code UPC used to routinely offset vents below flood level like underneath tub enclosures shower seats or cabinets, not quite legal where you live but Reach 4 idea eliminates that and notching into those 2x6 sleeper joists shouldn't be an issue. just really the AAV location suits you then its all good

 

[Arnav]

1.

Your wide 3 may be acceptable EXCEPT that you need to connect below the double fixture fitting instead of above. Then the drain into the floor under the lavatories does not get used. The wet vent carries the drainage over to the shower trap arm.

I am confused, isn't that exactly what the builder has done then? See pic "wide 3 annotated" as oppose to "wide 3 suggested." Unless what you mean is to add another vent between the shower and the tub but connect it under the lavs in addition to what's there today (in "wide 3 annotated"). If so, it is not clear to me how it is wet venting? just seems like we are adding another pipe to split the flow?

2.

I suppose a panel in ceiling might be an idea and less noticeable

No rules against AAV in the attic right? If so, I would probably do that since there is an accessible attic right above. I can leave a courtesy note in the vanity to a future plumber that it is there...

Attached please find pics for two more options I was playing with.

Option 1: The AAV is before the shower drain which I think is better. The venting is also to an interior wall which means there is more room for pipes without having to extra furr the exterior walls. I think i would still need to have a tiny tiny bit of horizontal vent to make into the wall.
In this case you would say the tub is wet vented?

Option 2: there is 9' from the shower trap to the AAV which is a foot longer than allowed so i guess that rules it out. The wall has to be further furred out since the vent will be over copper.

I think wet venting would be ideal in my case since it is hard to vent on the exterior walls without losing precious room. What would wet venting would look like?

 

[Reach4]

I am confused, isn't that exactly what the builder has done then? See pic "wide 3 annotated" as oppose to "wide 3 suggested." Unless what you mean is to add another vent between the shower and the tub but connect it under the lavs in addition to what's there today (in "wide 3 annotated").

Not in addition to, but instead of. The lavatory waste would all get diverted to join between the shower and tub.

Also "wide 3 annotated" aav has a problem in that the path goes horizontal below 6 inches above the lav rim. The aav can be 4 inches or more above the double fixture fitting, but that path must stay within 45 degrees of plumb, and the aav itself must be within 15 degrees of plumb.

 

[Arnav]

Also "wide 3 annotated" aav has a problem in that the path goes horizontal below 6 inches above the lav rim.

Yes, lets ignore the AAV. The builder did that so they can hide it in the vanity on the right (which breaks the rules..). I will fix the AAV, its not a problem. I understand what I need to do.

Not in addition to, but instead of. The lavatory waste would all get diverted to join between the shower and tub.

I think I finally get it. Attached is a pic of what i think you are suggesting (Option 0 below). Did I finally get it right? Thanks for the patience.Note that I propose to not bring it to the mid point between the shower and the tub so that the waste has less to travel. Does that still work? If not, I'll bring it to the mid way point.

I think i finally understand why what the builder has done is incorrect. He has two fixtures and no vent. The vent is at the end of the three fixtures whereas ideally the vent would be at the beginning of the stack or after the first fixture. Their pipe layout would have worked if the flow of water was the other way around (see attached pic - "what would have worked"). Did I get this right? Just trying to understand the physics behind it...

So all these would work and I can just pick one?
1. Option 0 - lavatory joins between the shower and tub. Attached to this post
2. Option 1 - AAV before the shower drain (pls see post above)
3. "what would have worked" - attached to this post

Thx!

 

[Jadnashua]

If you have access to the attic, you can run vent lines up into the attic, then combine them so there's still only one penetration through the roof. Atmospheric vents are preferred, as they don't wear out, unlike an AAV.

 

[Arnav]

Hi Jim, Understood. The issue and related delay would be getting the HOA to approve venting through the roof. Since I think dry vents need to run vertically, running 30' of pipe through the attic to the existing vent stack is not going to work either...

 

[Reach4]

1. Option 0 - lavatory joins between the shower and tub. Attached to this post

Both santees on their sides would each be changed to combos or wyes.

A bug crawling down the shower drain must need to walk no more than 8 ft past the output of the U-bend before meeting up with the wet vent from the lavs.

I am not a pro, and there may be something I have missed.

 

[Arnav]

I am not a pro, and there may be something I have missed.

Whaaaaaaaaat? You shouldn't have disclosed that. Totally passed for one...

Both santees on their sides would each be changed to combos or wyes.

Yes, of course. Was just mocking things up with the 2" leftovers I have on hand. I'll stock up this weekend.

A bug crawling down the shower drain must need to walk no more than 8 ft past the output of the U-bend before meeting up with the wet vent from the lavs.

Understood. At the moment it is 7' or less. If it exceeds that once the tub is chosen, that explain why the wet vent from the lavs may need to be closer to the mid-point.

Thx!

 

[Arnav]

Any objections from the pros to Option 1 above: https://terrylove.com/forums/index.php?attachments/option-1-annotated-jpg.75037/
Do the few inches of horizontal dry vent rule it out?

Thx for the help