How Best to Vent a Basement Bathroom

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richk

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I am putting a bathroom in my basement with a sewage ejector. My two issues are:
  1. How best to vent the basement fixtures. I think the answer is simply to tie into the tub's vent at D in image 1. The vent for the basement will be a toilet, shower, and sink that will vent through the sink, so that sink vent can tie into D. I also plan to vent the pump at D as well. So, if can tie into D, do I use straight tees, sani-tees, or wyes?
  2. As part of space-making for the basement bathroom, I am re-routing the waste from my main floor kitchen sink which currently has no vent. It comes down vertically to the basement and then runs horizontal behind a 2x8 header and then ties in just behind the tub at C. How and where can I tie this vent in downstairs.
Labels In Image 1 - this is a front view:
  • A - Current washing machine waste. This will be re-done (that is why I have the temporary pool hose running to it now. In the end it will just go to a slop sink.
  • B - New wyes for ejector pump waste and re-routed main floor kitchen sink.
  • C - Tub waste.
  • D - Tub vent.
  • E - Main floor bathroom sink waste.
What can't be seen in this picture is the current main floor kitchen sink waste line. That is to the left, behind a 2x8 header (which is behind E). I am going to remove the header (already relocated the supports) because the bathroom will be in that area. I will also need to re-route the kitchen sink waste. I will run it back to the wall, along the wall, under the window, and to the lefthand side wye at B.

front_view_2.jpg


Labels in Image 2 - this is a side/rear view:
  • C - Tub waste.
  • D - Tub vent.
  • F - Main floor kitchen sink waste.
rear_view.jpg


So, the only accessible vent down here is D from the tub. Can I tie all three things into this (basement bathroom group, ejector pump,kitchen sink)?

If the kitchen sink must vent higher than itself, I might be able to run it the 8" wall upstairs. It wont be easy, but in that case, what is the best route to take. The sink waste will be re-routed to run along the wall and under the window and the vent could go there as well, then come around the stack and go into the ceiling next to D. Im not thrilled about opening that wall between a finished bath and kitchen though.
 

hj

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Actually, you cannot connect ANYTHING to "D", at least not until it gets at least 6" above the rim of the tub, and even that would be ignoring the 42" requirement. If you are going to vent the sink with a tee below the floor, that is also a useless and improper way to do it. Refer to my previous comment about knowing how to vent.
 

Reach4

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Can you run a new 2 inch vent pipe to the attic?
 

richk

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"Refer to my previous comment about knowing how to vent."

But isnt that the point of a forum such as this... to ask questions?
 

richk

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"Can you run a new 2 inch vent pipe to the attic?"

And once in the attic, then through the roof? Or connect to the existing 4" that already goes through the roof. Then in that case, all of the basement fixtures and the pump would vent on that?

Actually, it isnt an attic though, it is a small crawl space (knee wall). My house is an undormered cape. So a real PITA to work in there if I could even fit at all with enough room to move around.

There is also the possibility that I can get to the 8" wall on my main floor by going through the ceiling right next to D. If I did that, I could maybe tie into the main bathroom vent the same way the tub is doing, perhaps right next to where the tub ties in. I have a little bit of access behind my refrigerator or the mirror in the bathroom, which are back to back on opposite sides of the 8" wall. Does that provide any possibilities?

I would imagine many houses have a similar setup to mine, where only a tub vent is accessible in the basement. Do all basement bathrooms install a new vent?

If it helps, I am not getting this inspected. So my main concern is safety, not passing code--I'm not sure how much, if at all, the two diverge.
 
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Reach4

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Tub vent is not 2 inch ID. But tying into that line as high as practical is probably going to work in practice. I am not a pro or even a good amateur. Just read some stuff, and I have a friend who has vented his septic pit with 2 inch tied into an existing 1.5 inch vent pipe. However that existing vent was for a basement laundry tub. So it was already a clean vent-- just undersized a bit according to newer codes.

How much room would you need in your crawl space? If you shine a light up, can you see a path? Better yet, at night, put a bright light where the existing vent pokes up into the crawl area. Can you see the light from a dark basement? There would normally be fire blocking stopping the light. But maybe you will not have that. If you can see light, you may be able to fit a new pipe as easily as some other options. I expect it would have fewer hangers than normal.
 

richk

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if I could get it up to the crawl space what would be best to do after that? Put it through the roof, or tie into the existing 4" ? Or does it not matte, and I would do whatever is easier.

Does getting to the 8" wall between the main floor kitchen and bath have no value?

And what is the purpose of tying into the tub line above the level of the tub? Is it so that, if the tub clogs, it doesnt run into the vents of the lower fixtures? My tub hasnt clogged in 15 years so if that is my only concern it isnt much of a concern. Of course, if it is a syphon/vacuum issue and I will be pulling water from the traps of other fixtures then it is a different story.
 
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Reach4

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If you can tie into an existing vent, that is best. If you penetrate the roof, you will need to get a special shingle that is often called roof vent flashing. Lead is the classic material, and will last forever usually. There are other materials that are cheaper that are often used.

I had a lead flashing installed by a roofer when I did a roof penetration.
 

richk

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I will need to look tonight and see if it is possible. If there is a firestop or something that prohibits me from running a new vent to the crawl space and tie it into the existing 4", then i think my options are (all incorrect of course):

1) Tie vents, if possible, in the 8 inch wall on main floor (still not sure if this is acceptable). I would do this above the level of the bathroom sink which would be also above the level of the kitchen sink. Not sure if I will have the room to do it yet.

2) Tie all three vents into the tub vent even if it is not correct. My concern here is safety. If it is just a matter of being a problem if the tub line clogs, I am really not overly concerned. If it is a vacuum/syphon/letting sewer gases into the house issue, then it is a different story.

3) Tie the basement fixtures and pump into the tub. Leave the kitchen sink with no vent... it doenst have one now and works just fine. In fact, it is actually two sinks (a main sink and an island sink) as well as a dishwasher that come down that line F in image 2. Has been this way for more than a decade and have never had an issue.

Of course, I could scrap the idea of the bathroom altogether.

I'm just trying to avoid the crawlspace. It is a tight spot and I'd be working lying on my side. Not something I want to do with a sawzall which I would use to cut the cast iron (did it in the basement and went smooth enough). Plus lying on my side, sometimes my back goes out and I need to roll over and crawl to the nearest chair to help myself up. Might be tough in the crawl space.
 
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richk

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Sorry about that. I didnt see the instructions that say I can only ask easy questions. My bad.
 

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I mean really, what's the value of a forum if only questions as simple as "how do I fix my leaky faucet" are given an answer, and any more complex situation is treated with comments such as:

"From that, if I interpret it correctly, and even that is questionable given the way it is written, implies that you have absolutely NO IDEA how to run a vent properly."
https://terrylove.com/forums/index.php?threads/wye-within-6-above-flood-level.59800/

So, in leiu of a helpful answer, you criticized my writing and scoffed at my lack of knowledge.

I would imagine the proprietor of this site wants it to be flooded with as much information about as complex do-it-yourself issues as possible. What's the point of a forum where a visitor cant search for and ask for detailed info about things they cant find anywhere else.

So what is you solution for me... hire a plumber? Is that what this site is for? I'm sure Terry Love would prefer me to find all of the info I need from this community than to leave.

So keep the rude comments coming--so far that's three and I've been a member of this site for about 24 hours.
 
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hj

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A bit "testy" aren't we? Do you have any idea how LONG we go to school AND work in the trades to find out the answers to the questions you want a "simple answer" for? I learned a long time ago that if you try to DESCRIBE how to do something, the other person may interpret it the way he THINKS it should be, NOT the right way. I assume you are counting like the old man who was going to town with his wife in the wagon. The horse pulling the wagon stumbled and the farmer said 'one'. A little later it stumbled again and he said "two". Further down the road it stumbles a third time and he said, "three", pulled out his gun and shot the horse dead. The wife exclaimed, "What did you do that for? He was old but doing his best". The farmer turned to her and said, "One".
 

richk

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I do. Please take no offense. In fact I was just explaining to my wife confusing this stuff is and how hard plumbers work.

But, again, I (and many others) come here for advice. What's the point of coming if we arent going to get it. I'm not looking for easy answers, just to learn things that I need to know in order to complete a job. I could spend the next few months reading books on plumbing, etc. but that's what this place is for... quicker access to good information.

In any case, and that aside (I hope) I am posting another pic. This one is what is behind my main floor refridgerator. It is the pipes of my bathroom which are right above the pipes shown in the first two pics. There was a "mystery" pipe as my father called it because we didnt know where it led. We suspected it was a vent of some sort--but it wasnt venting anything. It was just a capped stub between two joists and flush with the subfloor that can be seen above the basement joists. It is 1.5"

It turns out it is connected to the main floor bathroom vent. It is C in the pic. A little hidden behind the joist but can be seen.
So:
C is an unused vent, accessable from the basement, that ties in to the main floor bath
B is the main floor bath waste
A is the vent from the tub.

From what I remember, the cap near the bottom of B was, at one time the waste for the kitchen sink (the kitchen has long since been remodeled and the sink moved further away.

With this area open, I can also get a clear path to my crawl space and can run a 2" vent if needed.

So, there are three vents I need in the basement.
- the pump
- main floor kitchen sink
- the new basement bathroom group

I think I can tie the sink into C. It is not 6" above the rim, but rather flush. And not 42" above the floor, but 36" But it was plumbed that way when the house built so it must have been to code at some point. Can I use C for the sink vent?

Can I also tie the bathroom group into this? I can cut into one of the horizontal pieces and tie in there as well.

Then I could run a 2" into the crawl space and tie that in with the 4" cast iron stack.

Anyone have any thoughts on how to run the three vents with the situation I have?

BACK_PIC.jpg
 

Cacher_Chick

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Forget about cutting into the existing vent. No vent can run horizontally below the flood rim of the highest connected fixture.
Running a new vent up through the roof and you will not need to disturb any of the existing piping. If you are not able to to install the vent flashing correctly, get a roofer who can.
 

richk

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On further inspection, the bathroom sink is about 34 inches tall. Not sure if the flood level is the rim in the front or if it is the three overflow holes in the back of the sink which are about 33 inches from the floor.

The vent is 36 from the floor. So, while not a full 6" higher, it is about 2" higher.

If the reasoning for the 6" difference is to avoid water entering the vent, wouldnt 2" be just as good as 6" ?

Is it safe to assume that, when the house was built, the fixtures were a bit lower? I guess that would be the 42" from the floor requirement--to handle future changes.
 
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richk

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Running a new vent up through the roof and you will not need to disturb any of the existing piping. If you are not able to to install the vent flashing correctly, get a roofer who can.

What about running a new vent into a crawlspace and connecting to the 4" vent just before leaving the roof?
 

Tom Sawyer

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As soon as I read "I'm not getting this inspected, so I'm a only concerned about safety" I know that the job is well beyond your abilities and comprehension. The only reason we have codes and inspections is safety. What most unlicensed DIY folks don't understand is that improper and un inspected plumbing installation are unsafe and can cause sickness, property damage and even death. It's why we're licensed and why the plumbers motto is to protect the health of the nation.
 

richk

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As soon as I read "I'm not getting this inspected, so I'm a only concerned about safety" I know that the job is well beyond your abilities and comprehension. The only reason we have codes and inspections is safety. What most unlicensed DIY folks don't understand is that improper and un inspected plumbing installation are unsafe and can cause sickness, property damage and even death. It's why we're licensed and why the plumbers motto is to protect the health of the nation.

You only read and digested the part of that quote you wanted to. The full quote is:
"I am not getting this inspected. So my main concern is safety, not passing code--I'm not sure how much, if at all, the two diverge."

Which is explicitly makes the point that I do understand the dangers involved. You cant tell me that no codes can be broken without violating safety.
I have read other posts written by, I think HJ himself, where states he has often (maybe always) installed sewage ejector pumps without running a 2" dedicated through the roof. A violation of code, but safe (I assume since he is a master plumber) nonetheless.

As far as being beyond my current knowledge, I agree. Again, that is why I am here.
 

Cacher_Chick

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It might be good for you to look around and analyze drawings and pictures of plumbing which has been given the "thumbs up". Start with the concept that every fixture trap must be vented. The plumbing code is the standard way of doing things correctly, and while there is a bit of variation in the code from state to state, they each accomplish the same thing, which is a minimum standard.

To answer your previous question, yes one could combine multiple vents together, if the stack going up is sized properly for all of the fixtures connected. More often than not, it is much more cost effective to run a new vent from the basement through the roof.

There is some good reading here, if you are interested

https://files.acrobat.com/a/preview/b05b04d3-791a-4704-b399-cf7a493e762d
 
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