Drain layout question

[miky]

We are in the middle of the renovation and we have to change the drain layout.

I attached a sketch of what I’m planning to do.

- the drain from roof to the basement and the vents will be 1.5” pipe

- the first floor will have a sink and washer – 1.5” pipes. The washer’s trap will be under the subfloor, and the washer will be only 2.2 cu.ft. The washer’s drain will be around 10’ and the vent will be added 5’ from the trap.

- the ground floor will have also a sink and washer. Just the washer will be around 17’ away from the vertical drain. The washer will be 6.0 cu.ft.

-the basement will have a sink, WC and shower.

Any other comments and suggestions would be appreciated.

 

[hj]

It would be a VERY "lenient code" if it allowed all of that to be done with 1 1/2" piping, and allow the washer trap and horizontal vent to be below the floor.

 

[Sponsor]

 

[miky]

Thank you for your response.
Regarding washer trap and horizontal vent we don’t have a choice. That’s the only way we can run these pipes. How would you do in this kind of situation? Any advice please.
The ground floor and the basement 1.5” vertical drain we are changing to 2”.

 

[miky]

I made some changes on the layout. Would it work that way?

 

[hj]

That is even worse and would NEVER pass inspection, assuming the inspector could stop laughing long enough to write up the rejection slip.

 

[miky]

hj,

I'm not a plumber and looking for a solution. Could you help me in this situation?

 

[MKS]

I am not a plumber.
Your vent for the first floor washer is a big p-trap, second drawing. Vents need to be able to drain. I believe this is why you received the worse reply.
Terry has recently responded to a similar situation. Sometimes a wall is made deeper or a 'chase' is created to accommodate the plumbing.

Two inch vent for the wc is pretty standard in the U.S.
I'm not sure the basement wc is vented.

 

[miky]

Thank you for your response MKS.
Are there any restrictions how the vent has to run?
Would this layout work better? The arm would be around 10”-12”.

 

[MKS]

Have a look here.
Helpful Plumbing Hints for Residential Construction by Bert Polk Plumbing Inspector Lincoln County
There is an island loop vent that may work and lots of helpful information.

 

[Reach4]

This will be an improvement:
1. trap arm labeled 4 ... it can be longer, but it can be 4 inches. That 4 inches is measured wider than your red lines, so it is hard to get under the minimum.
2. AAV avoids the question of whether you can use an island vent for a standpipe. AAV can double as cleanout. It will be accessible and removable. Alternatively, I think I read that Canada permits standpipe P-traps to be below floor level (US does not). Doing that, you could put a santee for the standpipe in the piping above the sink drainage joining. That would avoid an AAV. IMG_7.png illustrates what I am saying, but don't take this as authoritative. Check with your local inspectors. They maybe very helpful. They may not be.
3. Except for santees, all drain transitions from vertical to horizontal must be long sweeps (LS).
4. Increase vent through roof to 2 inches or even more. In snow areas, this is often required to be even bigger.
5. Standpipe should be minimum of 18 inches. There is a maximum that varies. 24 inches would be nice.

I am not a plumber. Some of this may be wrong, but I am confident that it is pretty close.