Draining/Venting Tips Needed

[illusion8055]

Hello everybody,

Your input and feedback on this is very welcome.

I am combining what used to be side by side bathroom and laundry rooms in my basement into one larger room and of course this necessitates moving plumbing.

The previous plumbing all seemed to be draining just fine.

Please see the attached photos for a reference:

My main areas of concern are as follows:

• The existing dry vent that I am tying into is 2". I presume given teh fact that there were no past problems that this is sufficient for this bath/laundry group
• Given that the shower is now downstream from the toilet will this be an issue with venting? They will both use the sink's wet vent
• Do all of my tie ins to the main horizontal line (shower, toilet, sink) need to be Y-shaped?
• As you can see the two vents will tie in at the ceiling below the joists. Is the way I have it drawn out OK? Ideally I would run the line straight to both areas but you can see some stuff gets in the way so I have to make that awkward shape. This vent ties into the stack that vents the kitchen. The kitchen sink does not drain through this stack.

Please let me know if anything is unclear about my drawings.

Am I on the right path here?

 

[phishfood]

Your washing machine drain needs to attach to the main drain downstream from the bathroom group. You can attach the kitchen sink/dishwasher drain into the same underground line that the washing machine line drains to, but the kitchen needs it's own vent. That vent can tie back into another dry vent line.

Your other questions.

2" vent will be fine.

That will be OK, as long as the washer line ties in past all of that.

Either wye or combination wye and 1/8th bend, which makes a 90 degree turn.

The planned venting routing should be fine.

 

[illusion8055]

Thanks for the reply!

So let me make clarify something. As is the kitchen/drain line that you see coming down on the far right upper part of the first pic connects to the main 4" drain.

What you're suggesting is running the laundry drain to the kitchen/drain and then perhaps running that in parallel to the main drain and connecting it AFTER the shower drain rough in? If so how far after? Not much room (if any at all) behind the shower tie in wye. Runs right up against the edge of the room.

I would still maintain the vent that I've drawn in for the laundry where it is?

 

[illusion8055]

Here's another view


From this angle you can see that the former laundry/bathroom sink drain (the vertical one in the foreground on the left) was upstream of the toilet/bathtub. So this was done incorrectly in the first place?

 

[illusion8055]

Oh no... I took another look and realized that it's a 1.5" vent... I'm thinking that may not be enough....

 

[phishfood]

I would have to look at the vent tables, but there are 9 Drainage Fixture Units on that vent, and I believe that 1 1/2" will handle that, depending on length of the vent. If your main line really is 4", then code requires a 2" vent somewhere. But my eyeballs are telling me that your mainline is 3"?

As far as the washing machine and where it ties in, I have seen inspections fail because washing machines were piped through a bathroom group, and I have also seen that get missed and toilets bubbling and gurgling when the washing machine discharges. They had to break up a concrete floor and reroute the drainage piping.

 

[illusion8055]

My main line is 4". I double checked.

So I Photoshopped up some shots to further clarify things, and also illustrate tying into the 4" main AFTER the bath group.

Is there a minimum distance to maintain between tying the laundry into the main drain and the wye for the shower?

 

[illusion8055]

For reference from another angle: