# Adding bathroom



## dielectricunion (Feb 27, 2013)

I'm adding on a master bathroom in my small (1100 sq ft) single story house. The main waste line and stack is about 15 feet across the house from new toilet location. Obviously, I need to add a vent in that bath to the roof, right? What would be the appropriate size? 3"?


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## mudpad (Dec 26, 2008)

If it is obvious, why do you ask if that's right?


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## mudpad (Dec 26, 2008)

Sorry to be an azz. I don't know the answer to your question:sad:


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## Gary H (Dec 10, 2008)

I'm not a plumber but I got a great book call jlc field guide. Volume 2. It gives some good info on stuff like that. Weather it's code or not , I don't know but it sure helps when trying to understand what the code is telling you.


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## ScipioAfricanus (Sep 13, 2008)

I too am not a plumber, but I play one in my mind.

15 feet does not seem like a very long run that would require a vent other than the ones you shall use at the fixtures.

Andy.


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## jar546 (Aug 13, 2013)

Your bathroom fixtures need to be vented appropriately. If there is already one vent through the roof, the rest of the fixtures can be vented off an AAV such as a Studor Vent but it must be accessible such as in an attic if you don't want to cut another hole in your roof. 

Will this work require a permit and inspections in your area?

Each fixture needs to be vented the right way and if you have to ask a generic question like that, I am pretty confident you don't have a clue what to do. JMHO


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## Oconomowoc (Oct 13, 2011)

Here is a wet vent where the lavatory drain (wet) becomes the vent for the two floor outlet fixtures (toilet & shower) so the drain in increased to 2".


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## rex (Jul 2, 2007)

That's how we do it here. I just call it vent in between.

Although, I always to try to catch the toilet first.


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## Oconomowoc (Oct 13, 2011)

rex said:


> That's how we do it here. I just call it vent in between.
> 
> Although, I always to try to catch the toilet first.


Rex. Do you guys do this - "horizontal wet vent"


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## Gary H (Dec 10, 2008)

I always thought the wc had to flush after the sink .


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## Gary H (Dec 10, 2008)

Never mind. I was looking at it upside down.:laughing: Good thing I'm not a plumber.:whistling


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## Oconomowoc (Oct 13, 2011)

Gary H said:


> I always thought the wc had to flush after the sink .


Every fixture needs a vent so let's work through this and identify each piece of pipe as it moves along. I'll grab a pen.


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## Gary H (Dec 10, 2008)

Ok. What's the difference between wet and dry vents?


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## Gary H (Dec 10, 2008)

Oconomowoc said:


> Every fixture needs a vent so let's work through this and identify each piece of pipe as it moves along. I'll grab a pen.


Cool more drawings.:thumbsup:if it wasn't for pics I would be lost on how plumbing is layed out and the reasons of why it needs to work a certain way.


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## Oconomowoc (Oct 13, 2011)

Here is a wet vent.

In this scenario the lab drain is also a vent. What makes it a vent is the pipe diameter is increased to 2" to allow both air & water from the drain. It does two jobs.

Wall outlet fixtures vent floor outlet fixtures.

Look at at this photo.


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## Oconomowoc (Oct 13, 2011)

OK

So we are using the lavatory as a vent right? Well, what confuses a lot of people is how can that be tied in.

Because it is wet that 3 x 2 wye can enter the main line that serves fixtures in any direction but it MUST be a wye and not a T.

Also. The wet vent (which is nothing more than a oversized sink drain) enters the drain between the two most upstream fixtures.


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## Gary H (Dec 10, 2008)

Is the drain after the last tie in 3"? And can it be 4"?


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## rex (Jul 2, 2007)

Oconomowoc said:


> Rex. Do you guys do this - "horizontal wet vent"
> 
> 
> 
> View attachment 98615


Oh, yeah, but I'd try to catch the toilet down stream, just cause I like doing it that way. Either way would pass.

.


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## Oconomowoc (Oct 13, 2011)

Gary

When laying out fixtures and vents first identify floor outlet vs wall outlet.

Next. Wet vent vs dry vent.

Look at the drawing....

The left side is vented by means of a wet vent. The right side is vented by means of a dry vent.

OK, see what is similar? Let's first identify the floor outlet fixtures. In both drawings we have 3 right?

Toilet
Shower
Bathtub

On the left side drawing see where the sink (wet vent) enters the drain line? Between the two most upstream fixtures right?

OK, what about the right side drawing? Same thing right?

The layout is similar....... almost.

I'll make a drawing.....


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## Gary H (Dec 10, 2008)

Mike,

It's the same but for the dotted line. So that must be a change in the venting right?


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## Oconomowoc (Oct 13, 2011)

Gary H said:


> Mike,
> 
> It's the same but for the dotted line. So that must be a change in the venting right?


Yeah. I made a drawing but it keeps saying the application just crashed so I cant post it from my phone.


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## Oconomowoc (Oct 13, 2011)

Here


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## Oconomowoc (Oct 13, 2011)

It posted. Give me a minute to write


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## Gary H (Dec 10, 2008)

I'm getting it. But what would the reason to change the venting from wet to dry?


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## Oconomowoc (Oct 13, 2011)

OK. To understand wet vents is to first understand dry vents and how fittings are connected. 

Forget layout for a minute because that's easy. 

In the above drawing used the water/waste? A plumbing drain is designed to never exceed half the diameter during calculated usage. We call this a "spring line" Gary. 

Well, if it never gets more than half way full that tells us the upper half is dry right? Right.

So that is where dry vents tie in and they do this by means of a "T" but because its dry you can also use a "wye".......but nobody does.

That area that is dry is called the "upper quadrant".

I'll try and draw again.


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## Oconomowoc (Oct 13, 2011)

Gary H said:


> I'm getting it. But what would the reason to change the venting from wet to dry?


It's faster Gary. Think about I for a second, 99% of the time we have a lavatory to deal with so it's efficient to use the drain as a vent.


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## Oconomowoc (Oct 13, 2011)

This is the upper quadrant. Dry area vs wet area.

If a vent is dry you never want to tie in below spring line. Why? Because it cuts off the vent.

This drawing shows the lowest spot you can rotate a 3 x 1-1/2" T.


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## Oconomowoc (Oct 13, 2011)

Now imagine instead, a full 3" T.

The upper quadrant is pretty small because it would touch the waste right? That is all you need to know about dry vents for all practical reasons.


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## Gary H (Dec 10, 2008)

It's making sense now. What about those studder? Vents that they sometimes use. What are the purpose of them?


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## Oconomowoc (Oct 13, 2011)

Here is something that many people can't grasp. Distance.

Wet vents have no max distance. You can literally go 5 miles if you want.


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## Oconomowoc (Oct 13, 2011)

Gary H said:


> It's making sense now. What about those studder? Vents that they sometimes use. What are the purpose of them?


It's a one way check valve Gary. So it can only suck in air and not blow air out. 

Anyhow, it simply acts the same way. In Wisconsin we can't use them on sanitary crocks and laundry boxes but we CAN use them on utility sinks. I'll make a drawing.


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## Oconomowoc (Oct 13, 2011)

See the drawing on the left? Same rules Gary. The vent is venting 3 floor outlet fixtures. See how its tied in between the two most upstream fixtures? Same as a wet vent? Same as a dry vent?

See the drawing on the right? OK, the studor vent is now being used to vent a wall outlet fixture, in this case a sink.


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## Oconomowoc (Oct 13, 2011)

Studor vent on a laundry tub for a washing machine.


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## Oconomowoc (Oct 13, 2011)

Kitchen


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## Oconomowoc (Oct 13, 2011)

Or, if you have a fridge in the garage converted to a keg cooler.


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## Oconomowoc (Oct 13, 2011)

I have work to do......lol

Have a good evening


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## Gary H (Dec 10, 2008)

So those studer vents save labor and material when they can be used. Thanks mike for the lesson on vents.


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## Oconomowoc (Oct 13, 2011)

Gary H said:


> So those studer vents save labor and material when they can be used. Thanks mike for the lesson on vents.


Yeah but I rarely use them Gary. They do fail, the rubber disk sticks.


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## dielectricunion (Feb 27, 2013)

So when using the lav as a wet vent, the lav must itself be dry vented to the roof or nearby stack? Or it alone will provide vent?


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## Oconomowoc (Oct 13, 2011)

dielectricunion said:


> So when using the lav as a wet vent, the lav must itself be dry vented to the roof or nearby stack? Or it alone will provide vent?


Take a look at this drawing.

For all practical reasons this will be what a non-plumber would deal with. Remember he discussion? First identify flood outlet vs wall outlet right? OK. A sink is a wall outlet. In the case of a bathroom lavatory the drain (after it's vented) can either be a wet vent or just a drain. If it's just a drain you are done. Run it 1-1/2" and tie it in and the dotted line is a dry vent, and yes, it eventually runs out to the atmosphere...... which is usually a roof.

If the wall outlet fixture (lavatory) is being used to vent other floor outlet fixtures the drain after the point of vent needs to be 2" in diameter to allow both water for the lavatory and air for he other fixtures. 

So where is the point of vent? Where the dotted line ties in to the fixture drain. I'm both cases the dotted line ends up out the roof whether it's a wet vent or just an individual vent for a fixture.

Now, look at the drawing on the left. See how it's tied in on the horizontal? Why is that?

Well, here is where we get in to distance. The drawing on the left is the result of the unvented fixture drain being too far away and exceeding code distance. 

Distance
1-1/2" pipe runs @ a 1/4" per foot of pitch. How many quarters are in a 1-1/2"???? 6. So the distance is 6 feet max to point of vent. Why? Because water could cut off the vent.

A toilet on a 3" line is pitched @ an 1/8" per foot. So how long can a 3" toilet line be ran before it needs a vent? 

3" has 24 1/8's in it. The answer is 24 feet.


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## dielectricunion (Feb 27, 2013)

Thanks for all the info!


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## Oconomowoc (Oct 13, 2011)

Anytime


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## dielectricunion (Feb 27, 2013)

is this wrong since the WC is upstream of all fixtures? (nice drawing huh?)


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## dielectricunion (Feb 27, 2013)

oh yeah... definitely wrong. the vent needs to cut in behind the lav in order to serve all fixtures without independent vents to each. but WC doesnt technically need a vent, right?


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## Oconomowoc (Oct 13, 2011)

I'll make a drawing on my dry erase board. Give me a second.


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## Oconomowoc (Oct 13, 2011)

Here. Use the lav as the vent for the entire circuit.


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## dielectricunion (Feb 27, 2013)

ok another question, sorry.... cut a new 1.5 or 2" vent in the roof or run horizontal through attic (about 16') and tie in to the main stack?


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## Oconomowoc (Oct 13, 2011)

Here


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## Oconomowoc (Oct 13, 2011)

It's up to you. I personally do not like extra holes in a roof so I try and connect it to an existing stack.

If you do run it out out the roof do it like this drawing.


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## dielectricunion (Feb 27, 2013)

the roof is about the only thing on my house that _doesnt_ need to be rebuilt so id prefer not to touch it but i may have a harder time trying to tie into that cast iron. as you can see, im getting no work done, still in the planning phase and every time i get into something, another issue pops up that i need to educate myself in order to treat. im replacing the sloppy CPVC supply with copper and currently have this ridiculous jumper where i removed the old steel-to-leaking gate valve....








thought i might end up snapping off that awful galvanized and having to dig a 50 foot trench through neighbors yard to my meter....


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## Oconomowoc (Oct 13, 2011)

dielectricunion said:


> oh yeah... definitely wrong. the vent needs to cut in behind the lav in order to serve all fixtures without independent vents to each. but WC doesnt technically need a vent, right?


By the way, yes, the WC needs a vent. Every fixture needs a vent. Period.

It might look weird because the toilet is upstream but it is still being vented. The lav (wet vent) is venting the toilet AND the shower.


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## Oconomowoc (Oct 13, 2011)

dielectricunion said:


> the roof is about the only thing on my house that doesnt need to be rebuilt so id prefer not to touch it but i may have a harder time trying to tie into that cast iron. as you can see, im getting no work done, still in the planning phase and every time i get into something, another issue pops up that i need to educate myself in order to treat. im replacing the sloppy CPVC supply with copper and currently have this ridiculous jumper where i removed the old steel-to-leaking gate valve....
> 
> thought i might end up snapping off that awful galvanized and having to dig a 50 foot trench through neighbors yard to my meter....


FYI:

The only service calls I do on CPVC failures are threaded joints. Plastic products that are subjected to expansion and contraction do not do well in a threaded format. I use glued adapters.


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## dielectricunion (Feb 27, 2013)

im going to replace everything back to that valve and sweat copper so that CPVC thread will be gone.


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## Oconomowoc (Oct 13, 2011)

I pulled this out on a repair this week. This is a CPVC to brass fitting where it's all in one. The brass is mated to the CPVC in a plastic injection mold.


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## dielectricunion (Feb 27, 2013)

I heard those were much better than using PVC valves and threaded fittings. The guy who installed the stuff in my house got glue in most of the valves and they don't shut all the way. No shut offs to hot water tank either.


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## jar546 (Aug 13, 2013)

Oconomowoc said:


> Here is something that many people can't grasp. Distance.
> 
> Wet vents have no max distance. You can literally go 5 miles if you want.
> 
> ...


Just to clarify those statements, I will add my interpretation based on the 2009 IPC.

1) All fixtures must be vented and all fixtures still have a maximum distance to the vent connection.

2) Wet vents are under the same developed length limitations as dry vents.


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## Oconomowoc (Oct 13, 2011)

jar546 said:


> Just to clarify those statements, I will add my interpretation based on the 2009 IPC.
> 
> 1) All fixtures must be vented and all fixtures still have a maximum distance to the vent connection.
> 
> 2) Wet vents are under the same developed length limitations as dry vents.


Not in Wisconsin. We have our own code.


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## Oconomowoc (Oct 13, 2011)

jar546 said:


> Just to clarify those statements, I will add my interpretation based on the 2009 IPC.
> 
> 1) All fixtures must be vented and all fixtures still have a maximum distance to the vent connection.
> 
> 2) Wet vents are under the same developed length limitations as dry vents.


Minimum distance, in WI is 2 x diameter.


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## KillerToiletSpider (May 27, 2007)

Oconomowoc said:


> Not in Wisconsin. We have our own code.


No wet vents allowed here.


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## Oconomowoc (Oct 13, 2011)

KillerToiletSpider said:


> No wet vents allowed here.


How about outside the City?


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## KillerToiletSpider (May 27, 2007)

Oconomowoc said:


> How about outside the City?


I'm sure state code allows them in some form, but the tri county area where I work follows Chicago code in some form, one village here uses Chicago code dated 1992, which is two years before the approval of PVC pipe in single family homes.


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## Oconomowoc (Oct 13, 2011)

KillerToiletSpider said:


> I'm sure state code allows them in some form, but the tri county area where I work follows Chicago code in some form, one village here uses Chicago code dated 1992, which is two years before the approval of PVC pipe in single family homes.


That's gotta suck to be a plumber who lives on the border


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## jar546 (Aug 13, 2013)

Oconomowoc said:


> Not in Wisconsin. We have our own code.


That's not going to help the OP since he lives in Chicago.


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## Oconomowoc (Oct 13, 2011)

jar546 said:


> That's not going to help the OP since he lives in Chicago.


I have no idea where he lives. I post from my smart phone and the locations never show up. 

If you live in chicago let's see some drawings, photos, advice etc. Or am I the only one willing to do this?


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## jar546 (Aug 13, 2013)

Oconomowoc said:


> I have no idea where he lives. I post from my smart phone and the locations never show up.
> 
> If you live in chicago let's see some drawings, photos, advice etc. Or am I the only one willing to do this?


Right below his avatar it says chicago. It is good that you are helping him but its always a problem when there are two completely different codes between the area of work and the area the help is coming from. From what I understand, Chicago has a very different plumbing code and it sounds like Wisconsin does too.

The IPC for example states that there is no limitation on how close a vent has to be to a water closet since it is a self siphoning trap. That may not be the case in Chicago, WI or NYC for that matter. Who knows.


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## Oconomowoc (Oct 13, 2011)

jar546 said:


> Right below his avatar it says chicago. It is good that you are helping him but its always a problem when there are two completely different codes between the area of work and the area the help is coming from. From what I understand, Chicago has a very different plumbing code and it sounds like Wisconsin does too.
> 
> The IPC for example states that there is no limitation on how close a vent has to be to a water closet since it is a self siphoning trap. That may not be the case in Chicago, WI or NYC for that matter. Who knows.


In that case he would still be code compliant. In 99% of bathrooms a vent would never be that close anyhow. 

Mike


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## dielectricunion (Feb 27, 2013)

Still haven't changed my location. I just bought a single family house in Bloomington Indiana. Code here is very loose compared to Chicago. My basement is a nightmare between the cpvc supply lines and Romex all over, looks like a bowl of spaghetti. I'm replacing all supply with copper but I'm still debating whether I should rewire with EMT or just clean up the jumbled Romex job.


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