# vent under eave vs puncturing roof



## ben's plumbing (Oct 6, 2011)

jackdiy said:


> I have a stand alone 8x10 bathroom out on a ranch in an area that is often but not always windy. Let's say I need to add a new vent for the toilet. What is the value added of puncturing through the roof compared to just ending it under the eave? Is that extra foot or two of height going to save me from smelling the gasses?


 not sure where your located...but its code to exit out roof.... yes you can and will get sewer gas if you put under eave...ben sr


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## jackwashere (May 5, 2010)

ben's plumbing said:


> not sure where your located...but its code to exit out roof.... yes you can and will get sewer gas if you put under eave...ben sr


As long as I don't announce that it's a bathroom the county will not do anything about it. Don't need to register or ask permission to build anything I want under 120 sq. ft. The bathroom is 8x10. 

Will it matter that much that I puncture the eave and extend another foot above the roof? The eave is out in the open and not near any windows or doors.


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## Beepster (Oct 19, 2009)

Get puncturing the eave out of your mind. 

Is there not anywhere in the basement that you can tie into? 

If not, check with your building permit department to see if Air Admittance Valves (AAV) are allowed by code. 

Please do this under permit. Building inspectors are not that bad (usually). It will make resale a lot easier.

B


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## Alan (Apr 12, 2006)

What is with all these half-cocked hairbrained ideas? Why even ask if your response is going to be : "the county won't do anything about it if i dont announce that it's a bathroom"

Sure, you are 100% correct.

If you want the professional opinion that you came here to get : 

Plumbing code requires vent termination to occur in certain places. Under an eave is not one of them.

However : I figure you're just going to do it your way in the end anyway. 
Best wishes and happy holidays.


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## plummen (Jan 10, 2010)

Its a lot easier to get airflow over the vent which makes it easier to draw air into vent when it comes up through roof line.
Don't forget to increase to 4" a foot below the roofline to keep it from frosting over if you live in a cold area:wink:


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## joecaption (Nov 30, 2011)

If the roof is vented your going to just sucking in the sewer gases into the attic by doing it the way your suggesting.


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## paintdrying (Jul 13, 2012)

There is a real good reason not to go through the eave. Now it is going to bother me all day because I can not remember. It will not vent right, the gas can bellow back down right into a window. You could try and not vent everything and see how that works for you.


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## joecaption (Nov 30, 2011)

In order for the gas to be sucked out of the vent there needs to be air pasing over it to create a negative pressure. It's called a venturi.
http://library.thinkquest.org/C0122082/Venturi Effect/VenturiEffect.htm

Same thing happens with a chimmney.
http://library.thinkquest.org/C0122082/Venturi Effect/VenturiEffect.htm


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## jagans (Oct 21, 2012)

*Follow the Code*

The National Plumbing code, and the National Electric Code, and most other codes have developed over the years in response to what works and what does not work vis a vis life safety. They were not developed by a bunch of building inspectors sitting around a table thinking of ways to mess with homeowners. If anything, some of the codes are not stringent enough, because they are consensus codes, driven by cost. Since installing a vent through a roof is a fairly easy and reasonably priced thing to accomplish, what is your point?


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## jackwashere (May 5, 2010)

joecaption said:


> If the roof is vented your going to just sucking in the sewer gases into the attic by doing it the way your suggesting.


Not a chance. The eave is sealed off with trim, caulking, and several caked on layers of paint. More often than not the ranch is windy. It's between two mountain ranges. Air moves around alot out there. It's a wide open area.


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## jackwashere (May 5, 2010)

jagans said:


> what is your point?


I'm not trying to make a point. I'm simply measuring twice before cutting once.


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## jackwashere (May 5, 2010)

jagans said:


> vis a vis life safety


Please elaborate. Two problems come to mind. Is the gas explosive? If I turn on the light switch can that cause an explosion? Is the gas suffocating? Can somebody pass out or die from lack of oxygen? 

I'm asking because I want to know how concerned I should be not so much from the vent going through the roof but from leaky plumbing. Let's say the wax from a toilet seal is not set right and gas will leak out.


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## Beepster (Oct 19, 2009)

jackwashere said:


> Please elaborate. Two problems come to mind. Is the gas explosive? If I turn on the light switch can that cause an explosion? Is the gas suffocating? Can somebody pass out or die from lack of oxygen?
> 
> I'm asking because I want to know how concerned I should be not so much from the vent going through the roof but from leaky plumbing. Let's say the wax from a toilet seal is not set right and gas will leak out.


I think the stink would drive you out of the house before it ever concentrated enough to kill you.

B


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## jagans (Oct 21, 2012)

*Wax seal*

If the wax seal loses integrity it will smell in your bathroom letting you know you have a problem. You will also have water on the floor when you flush in most cases.

If the vent is run out through the roof, air passing over the pipe draws the gas out (Bernoulli?, High Velocity= Low Pressure?) if you point the vent down in the eaves, air hitting the wall below will flow upward and force backpressure on the vent, thereby forcing more methane into your home and out the broken seal 

The gas is methane, and yes it is flammable and potentially explosive, but I doubt that this will happen. Go ahead and try it if you want. Do you smoke?

:whistling2:


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## jackwashere (May 5, 2010)

jagans said:


> If the vent is run out through the roof, air passing over the pipe draws the gas out (Bernoulli?, High Velocity= Low Pressure?) if you point the vent down in the eaves, air hitting the wall below will flow upward and force backpressure on the vent, thereby forcing more methane into your home and out the broken seal
> :whistling2:


You misunderstood. I'm not pointing the vent down. The vent goes up all the time. I proposed ending the vent under the eave. Not continuing up through the roof. My eaves are sealed shut. Caulking, paint. No way for air to get in. Elevation roughly 7-8 feet. So what's the value added of puncturing through the roof and adding another 1-2 feet to the pipe? Lots of air will flow over the pipe under the eave. More air will flow over the pipe on the roof. Will the extra air save me? I can do it. I went to Lowes and they have these roof vent attachments with a rubber condom on it. You insert a 1.5 to 3 inch pipe through it and the rubber membrane wraps around it. Cheap, like $5-6. The problem is that I currently have asphalt shingles and the ranch is very windy. This will be replaced with a 24 guage metal roof. I don't like the idea of vents in metal roofs. They're problematic.


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## Alan (Apr 12, 2006)

I think this thread should just be locked at this point. We are beating a dead horse here.

:wallbash:


Vents terminate a minimum of 1 foot above eaves, not inside of them, under them, or whatever other tricky ideas you have. They run flat, or they slope toward the fixture served by said vent. Not up, then down, or down, then up, full of water, pine needles, or whatever else you might have blowing in there.


Drill a hole through the roof, install a flashing, put a pipe through it, and be done. I don't understand what is so difficult about this process.


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## ben's plumbing (Oct 6, 2011)

agree allan ...this guy does not want the proper way to VENT a fixture....so he can do it the way he wants...iam sure he will anyway.....what a waste of time...everyone have a good evening...ben sr


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## md2lgyk (Jan 6, 2009)

You seem bound and determined to do this your way in spite of all the sound professional advice you've been given. So I'm not going to bother suggesting what I think you should do. But I will tell you what I would do: I prefer to minimize roof penetrations (my current house, which I built and plumbed myself, has only one, the main stack). All the vents tie into it in the attic. I would run your vent pipe up into the attic and terminate it with an AAV if there's not another vent nearby to tie into. Some pros dislike AAVs but they are legal (here at least) and have been around for years. I do have one fixture (kitchen sink) that is vented with an AAV and have not had any problems.


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## jackwashere (May 5, 2010)

md2lgyk said:


> in spite of all the sound professional advice


if sound and professional advice came with cash to cover my losses I would gladly take it problem is that after all is said and done I am left to cover the cost of doing it wrong and then redoing it

I have to redo the vent system because I hired an expert plumber who messed up the job. I have to redo the roof because I hired an expert roofer who messed up the job. 

If I do things myself I may mess them up. But if I do I can only blame and be angry at myself. As it is I'm angry at experts and truth be told I have lost confidence in them. I have found that it's better to do some research, listen to people's opinions, then decide for yourself rather than to blindly follow people who claim to be experts. Now if all of your brilliant advice comes down to is "because it's code" then thank you. That in and of itself is of no value to me. 

That said I have benefited from all your good advice. It is even good to know what the code specifies. I will end my toilet vent above the roof not under the eave. You have convinced me that this is the smart thing to do. The vent will not penetrate the metal roof however. Instead I will use 2" furring strips instead of the 3/4" I usually use when doing metal roofs. 2" (1.5" actual size) of furring strips will create an air gap between the current roof (asphalt shingles) and the metal roof which will lead upward toward the ridge cap at a 1:3 slope. The ridge cap will have 2" holes bored in the front and rear of the gable covered only by a screen to keep the birds out. Also known as gable end vents. The gable end vent is approx. 10-11 feet above grade about the same height as the current vent ends. Please do not get spasticated and confuse this with an attic. I'm going to install a metal roof 2" above the current asphalt shingle roof. We're talking about using the air gap between the current roof and the new roof as a vent. See pix below...

http://tj.jjt.partyconnect.me/construction/cottage/

Notice the rocks on the roof? It gets windy on the ranch and asphalt shingles just do not pass the test. 24 guage metal with Kynar 500 infra-red reflecting paint should have been used in the first place.


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## jackwashere (May 5, 2010)

md2lgyk said:


> This, and your zany ideas of how to run the vent


Perhaps you didn't read what I wrote or you didn't see the picture of the rocks on the roof. Let me repeat it. Asphalt shingles do not pass the test on the ranch. It is often windy and they flap and break away. In windy areas there are two roof options that I know of. Ceramic tiles and metal. I don't like ceramic tiles because they act as a heat reservoir. They stay hot for a long time after the sun goes down and at night when you want it to cool down. A 24 guage metal roof with Kynar 500 (infrared-reflective) paint is the best solution in my opinion.

Here is a similar discussion to ours regarding vents and metal roofs...

http://www.diychatroom.com/f19/vent-pipes-through-metal-roof-120203/

which leads to this

http://www.diychatroom.com/f9/correct-way-flash-vent-pipe-metal-roof-74368/

which leads to the bottom line: The bottom line is that there is no good way to run a vent through a metal roof.

So having a metal roof is not standard on residential development. So every so often you get a by-the-book and do-it like everyone else contractor who does not like this solution and calls it zany. So what?


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## ben's plumbing (Oct 6, 2011)

jackdiy said:


> if sound and professional advice came with cash to cover my losses I would gladly take it problem is that after all is said and done I am left to cover the cost of doing it wrong and then redoing it
> 
> I have to redo the vent system because I hired an expert plumber who messed up the job. I have to redo the roof because I hired an expert roofer who messed up the job.
> 
> ...


 did we file all the plans ...get permits and hire professional people or did we just get people who were ok with not letting authorites know whats going on as was stated in one of your comments?????


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## jackwashere (May 5, 2010)

ben's plumbing said:


> hey jackdiy were you go....


It's a no-win situation. Break through the roof is bad. Don't is bad. There is a perfectly good third option but you guys don't like it because it's not kosher. End of discussion. Why stick around to aggravate each other? 

Regarding your concern about doing things legit. I will gladly explain things in private email. It's a touchy subject which I prefer not to discuss on an internet forum. Write to me and I'll reply: [email protected]


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## jagans (Oct 21, 2012)

*Again*

*if wind is the issue, why didnt you just put on a fully adhered 60 mill epdm roof, turn it down at the perimeter, and nail on a .050" aluminum drip edge and strip it in with 9 inch pressure sensitive flashing? Then you could easily pipe the vent through the roof, and install a pressure sensitive witches hat flashing on your pipe. To keep it cool, coat it with white acrylic.

Last Attempt, you dont listen
*


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## Gary in WA (Mar 11, 2009)

Getting off topic and plain rude, thread closed. OP, start another thread for new questions, if needed, thank you. Gary


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