Adding basement kitchen DWV question

[TurboR1]

Hi,

This is my first post. I'm a DIYer and have avidly avoided plumbing if possible but I'm finishing a basement and want to add a kitchen. It will be directly below the main floor kitchen. I've tried to read and understand the code but I don't know enough for it to make sense. Attached is a poorly sketched drawing of the current plumbing layout, the proposed layout, and a picture of under the sink. The current main level sink drain does a horizontal 90 degree to the right. I'm thinking something like this island vent but am unsure if it is approved. What are your ideas that I can do without tearing out the main kitchen walls/cabinets and still be in code. Any info or ideas would be greatly appreciated.

 

[frodo]

if you want to plumb an island vent, you need to bust the floor up
at the kichen sink stack, and trench/bust a ditch to where you want the island

 

[Zanne]

Ok, a few questions:
1. Is the plumbing from the main floor kitchen inside of a wall in the basement or is it exposed?
2. How far away will the new sink be from the existing drain pipe?
3. Do you have photos of the basement area where you want to put the kitchen?
4. Have you checked local building code to find out if adding a kitchen in a basement is allowed in your area? (Some jurisdictions don't allow basement kitchens)

Does anyone know if it is ok to wet vent a downstairs sink to an upstairs one? I'm guessing "no".

I could be wrong, but I think you will need a branch vent going up through the wall to at least 6" above the flood level of the upstairs sink to tie in to the existing vent pipe.

If you don't want to put the basement vent pipe inside the existing wall, you can build a pillar or have a bulkhead to run it up.

 

[TurboR1]

here are perhaps a better sketches of my idea.

1. The basement is exposed.
2. within 3 feet.
3. See picture below
4. Local code allows basement kitchen.

I didn't think wet venting was allowed unless on the same floor. That's why I was thinking of turning the current main level kitchen drain into a vent line using an island loop and connecting in the basement.

Can someone describe what the "flood level" is?

 

[TurboR1]

This is currently how it sits.

 

[KULTULZ]

Can someone describe what the "flood level" is?

See if this helps explain the term-

Each fixture also has a flood rim, or level at which water will begin to overflow. Most fixtures also have an overflow, which is a conduit for water to drain away, when the regular drain is plugged, before the water actually overflows at the flood rim level. However, water closets and showers (that are not in bathtubs) usually lack this feature because their drains normally cannot be stopped.

SOURCE- https://en.wikipedia.org/wiki/Plumbing_fixture

 

[TurboR1]

See if this helps explain the term-



SOURCE- https://en.wikipedia.org/wiki/Plumbing_fixture

thank you. So speaking about a kitchen sink would the top of the sink be the flood line since there is no conduit to divert the water from flooding?

 

[KULTULZ]

So speaking about a kitchen sink would the top of the sink be the flood line since there is no conduit to divert the water from flooding?

Correct...

 

[frodo]

negative... you have to have a vent to atmosphere.

you can not use the drain stack for the 2nd floor as a vent

to add your sink, you will need to add a vent that ties in 6'' above the sink [flood level] on the sink upstairs



flood level on a toilet is top of bowl
on a shower it is at 4'' the top of the curb.. exception,,,HC shower it is 1/2'' above floor


flood level is when the water falls out of the fixture onto your feet
flood level rim is where the over flow occurs
a mop is to clean up the overflow

 

[TurboR1]

negative... you have to have a vent to atmosphere.

you can not use the drain stack for the 2nd floor as a vent

to add your sink, you will need to add a vent that ties in 6'' above the sink [flood level] on the sink upstairs

View attachment 14112

Dang, that means I have to tear out my kitchen cabinets I was hoping the island loop was kosher.

Thanks for replying to my questions.

 

[frodo]

Dang, that means I have to tear out my kitchen cabinets I was hoping the island loop was kosher.

Thanks for replying to my questions.

not necessarily,,you do not have to tie into that vent

you can tie into any vent as long as you tie in 6'' above the fixtures flood level

or,,run the vent out the roof,

or,,run it up into the attic, then tie into a vent

I have in the past...drilled a hole in the back corner behind the fridge.

run the vent into the attic, then tie into the sink vent

 

[KULTULZ]

Follow frodo's suggestion of an AAV (Air Admittance Valve).

A install is shown below w/o GD install-

 

[Zanne]

Can you have an AAV on a fixture that ties in to a drain that comes down from the floor above?
I might be wrong on the rule, but the highest fixture served by that upstairs drain is the 1st floor kitchen sink; hence the basement vent needs to tie in above the 1st floor kitchen sink.

You don't have to tear out cabinets-- you can cut holes in walls behind cabinets to access stuff if need be-- that way it will be disguised. You can also do as suggested and tie in to the vent in the attic. It doesn't have to be exactly 6" above the flood level-- it just has to be a MINIMUM of 6" above it.

I just realized I don't think Flood Rim or Flood level is on the plumbing glossary list. /facepalm

Editing to add: If you do use an AAV, make sure it isn't inside a wall. They can fail in 2 to 5 years depending on what the climate is like where you live. They could last longer, but it is best to be prepared to replace them if they fail.

 

[KULTULZ]

I just realized I don't think Flood Rim or Flood level is on the plumbing glossary list.

!!!AHA!!!

Were counting on you here 'ya know...

Editing to add: If you do use an AAV, make sure it isn't inside a wall. They can fail in 2 to 5 years depending on what the climate is like where you live. They could last longer, but it is best to be prepared to replace them if they fail.

You can hide them and be accessible-