Rough Drain/Vent Plumbing In Upstairs Laundry/Bathroom

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rchesterton
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Rough Drain/Vent Plumbing In Upstairs Laundry/Bathroom

Post by rchesterton » Sun Mar 17, 2019 6:42 am

I am putting a second floor laundry/bathroom on the second floor of my house. Running supply lines is simple, but I am looking for direction for plumbing in the drainage for toilet, sink, laundry and tub. I am wondering if I should run one main drain pipe down through the first floor and straight into the basement where I then run it over to the stack, or if there should be separate drains that I use y fittings for to tie into a horizontal run into the stack in the basement?

The picture shows the room. My plan is also included. I have reinforced the floor to compensate for the vibration and weight of all of the new fixtures/appliances. The regulations / efficiency / best practices of drainage is really the greatest challenge for me at this point (just not knowing how to do it).

The stack is about five feet over to the right, by the way, in this picture. I would think that running my drains straight down to the basement instead of opening up walls and going through studs would be recommended. Right?

And, if so, would I create one main drainage point going down to the basement and tie in the sink, tub, laundry and toilet all to that one drain? It doesn't seem like there would be enough room to build in adequate pitch for everything going into one. So, if that is the case would I create two drains? One for the laundry and sink, and one for the tub and toilet?

The plan I have attached shows where I want to place things. I have placed a yellow highlighted dot to indicate where the stack is. I cannot access from this room - just downstairs or through the wall in the adjacent bedroom. There are two pictures of the room I am preparing. The wall you see is where I would run the drains down (it is an external wall but only for a couple of feet (then it runs into an internal wall downstairs (insulated).

You see that I blocked the floor where the washer and dryer are going and sistered joists from outer rim to center (above i beam) where the tub and toilet will go. One other thing...that closet in the plan was an original idea but we are not going to do that - washer and dryer will go right to the corner (and I will remove that door).
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Shannon
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Re: Rough Drain/Vent Plumbing In Upstairs Laundry/Bathroom

Post by Shannon » Sun Mar 17, 2019 8:40 am

This really is not an easy thing to figure out without seeing everything involved below also, and pictures is really not enough.

Basically because your joist run the direction they do I would think running right to the basement and then over to the main stack is likely your best bet.
I would run a main stack through the roof and down the wall behind the toilet 3" min.
The tub should be able to drain to that with a vent loop into the main stack above the toilet.
As for the laundry and sink They should be able to drain together so one of them will have a drain in the floor over to the other then down to the basement . They will both need to vented as well up into the attic and over to the new stack should work.
Once everything is in basement I'm not sure what you have down there so into the floor and over to main sewer is likely best?
You likely wanna have a plumber come in and have a look cause i'm kinda guessing here without first hand seeing exactly what all going on. And also I am not a plumber or familiar with codes for exactly where you are.
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rchesterton
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Re: Rough Drain/Vent Plumbing In Upstairs Laundry/Bathroom

Post by rchesterton » Thu Mar 21, 2019 6:37 pm

Thanks for that input - it was very helpful and at least gets me started thinking the right way. I have a stack very easily accessible once I get through the floor downstairs. I'll go straight down and then over to the stack.

There are no obstacles in the wall or downstairs that are going to limit this (I know, I'm lucky so far).

Assuming that (that it is indeed a straight-forward drop down and over to the stack) I have a couple of questions:

1. What is the recommended pitch from fixture to riser? Is it 1/4 " per foot regardless of appliance?

2. Is it acceptable to use mechanical vents inside the walls instead of running them up into the stack at the roof penetration point?

3. Do all fixtures have a trap right after the drain? Tubs included, right? That's what prevents fumes from coming back in through the vent/drains, correct? What about washer - does that need a trap too?

4. Is it possible to have one riser going straight down the wall into the basement and have all 4 fixtures tie into that?

Thanks

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Shannon
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Re: Rough Drain/Vent Plumbing In Upstairs Laundry/Bathroom

Post by Shannon » Thu Mar 21, 2019 8:18 pm

1. 1/4” drop per foot of horizontal travel.

2. APVs need to be accessible and not everywhere allows them to be even used.

3.Yes everything needs a p trap except toilets , they are built into them.
FYI laundry should be 2” drain lines.

4. yes you could have one main drain it would need to be 3” min.
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