Venting questions for a basement bathroom


Old 07-03-16, 11:39 AM
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Venting questions for a basement bathroom


I'm trying to add a bathroom in my basement, and from my research I don't completely understand what is necessary to be considered a vent.
The bathroom will be immediately next to my main stack. From my understanding the stack constitutes a vertical wet vent, correct?
Does this mean if my fixtures are less than the required distance between the trap and the vent I can just connect the toilet and sink drains to the main stack and be done?

From the basement I can see the trap of the toilet on the floor above and that seems to be the case... the drain from the washer comes in but otherwise it connects directly to the main stack.

I really appreciate any answers and advice!
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Old 07-03-16, 04:00 PM
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You must vent any new connections that are added to a plumbing system. Being near a stack is irrelevant. The fixture that sits above the finished floor would be your bathroom sink. Extending that pipe to your existing vent stack will give sufficient air for the entire bathroom group.
Old 07-03-16, 09:12 PM
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Thanks for the reply. I had been looking at things like this to try and understand what was allowed:

Which specified the distance that the vent pipe coming off the fixture drain must be from the trap, as well as made it sound like the stack itself was a vent. Thus I thought if I had the drain from the fixture go directly into the stack and and it was less than the vent distance, I'd be all set.

Apparently I was mistaken. So currently on the lower level I don't think there are any existing vents for me to tie in to, everything is a drain line into the stack. There is a bathroom directly above, but none of the plumbing is exposed. I am guessing this means I'll have to cut through the floor and then through the bathroom wall to tie into an existing vent?
Old 07-03-16, 09:20 PM
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Technically the stack is a vent but at the basement level it's considered a wet stack as liquids flow thru it. In the upstairs bathroom... no water producing devices are above it.

Not sure if you can tie into an existing bathroom vent.
You may be able to run a vent line up to the attic thru a closet.

The plumbing pros will stop by and add their ideas.
Old 07-04-16, 06:54 AM
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Yup as Pete states need to run vent for that bath up into the attic or out through the roof some how..

An alternative is to use a AAV vent ( studor vent ) if code allows it..
Old 07-04-16, 08:01 AM
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It seems like fewer holes in my roof would be a good thing... is there any reliable way to locate existing vents that I could tie in to? It sounds like no matter what I'm going to be busting some dry wall.

Alternately, could I just put a hole in the rim joist and vent outside that way?
Old 07-06-16, 07:23 PM
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Unless you have vents accessible in the attic, the easiest way is to usually go up through the roof. It's pretty easy to create a weatherproof seal if done correctly - or asking a roofer for some help. It's sometimes easiest to find vertical access via the back of a closet up to the attic/roof. It's usually not as hard as it sounds.

You can go out the side of the house, but you still have to go up vertically likely to above the roof level. It's easy, but usually considered rather ugly.
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