Hi, here is a sketch of a recommendation for drain pipes for a bathroom remodel. For the toilet to be the most downstream fixture and the tub and shower not to have too many degrees change of direction, this is the recommendation. The toilet is downstream from the kitchen sink and the vanity and it drains into the 4” drain pipe first, above a double 4x2x2 wye that drains the tub on one side and the washing machine on the other. Is this necessary though and will it cause problems?

1. The tub, toilet, vanity, and washing machine are each in their own 90 degree quadrant around the drain pipe.
2. The distance from the crawl space floor to the bottom of the joists is 21”.
3. Each fixture except the toilet has its own vent running up the attic (one story one bedroom house with crawl space).


Hopefully one of these two links works:
[i.postimg.cc]



Edited 2 times.

wow... you put a lot of work into that drawing but i can't understand most of it.
a single line drawing from the side would be much easier to understand.

mark the size of each pipe and draw vents as dotted lines.

[www.pinterest.com]

How’s this? I’m not the greatest artist but I think this shows the idea.

[i.postimg.cc]



Edited 1 times.

very good.

yes as long as the lower floor fixtures are vented then you are OK.

the kitchen needs to drain into the 3 inch downstream of where the vanity ties into the toilet drain. the vanity acts as a wet vent for the toilet

Ok, thanks a lot, this is really helpful. The cast iron elbow at the bottom of the existing soil stack is rusted, then a couple feet downstream of that in the building drain, there’s a section of the drain where an iron pipe for the shower was cut in that needs to be replaced as well. Since that had to be done, I’m wondering if putting in a 4x4x2 combo wye at that point would make sense for the shower and washing machine to drain into instead of in the main sill stack.

Here’s the diagram where I’m trying to show tying the shower and the washing machine going into the building drain one on top of the other, so that the combo wyes for them can be oriented exactly to the incoming angle, instead of trying to line them up to a double wye at the same level. There is 21” of space below the joists to the ground at that point, and the building drain is a few inches below the ground in the crawl space at that point.
The tub is about two feet from the building drain at that point, and the washing machine is at nine feet, so stacking the combo wyes would help with the fall as well. Is there a minimum vertical distance between two incoming drains to the vertical in this situation?

Also, for the cleanout, is a two way cleanout just upstream of the 4x4x2 combo wye ok, to minimize mess if it had to be opened, or would a standard cleanout at the base of the 4” soil stack make more sense?

[i.postimg.cc]