I have new construction with 4" drain and 2x4 exterior walls. I am building a detached shop/living quarters with 2x4 walls and all plumbing is in one exterior wall.

  1. how would you run it? :)
  2. are cripples considered load bearing and does the 60% rule if doubled apply?
  3. can i go thru 3 cripples and then wrap around the king/jack studs? code says you can drill thru 2 on load bearing so question 2 is key. I could cut the window shorter and take bathtub vent straight up if needed I guess.
  4. if tying in vent lines on the horizontal how much angle required? just thought of this - can probably lookup myself.

I have no idea what im not asking. sorry. enter image description here

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    Any reason you can't frame the plumbed portion of the wall (the bathroom and kitchen) in 2x6? That's the usual m.o. I'd have done the entire wall. – isherwood Dec 31 '20 at 1:30
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    Off topic: Isn't treated lumber required against the concrete where you are? – isherwood Dec 31 '20 at 1:32
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    Truly, this seems like a failure to plan. Either build a thicker wall if you want it hidden, or a pipe chase on the face of the wall, or hang that pipe out there in all its glory on the face of the wall. – Ecnerwal Dec 31 '20 at 1:48
  • Off topic, but it appears your water supply lines will come down from the attic. This precludes slab leaks, but does expose vulnerable pipe materials like PEX to rodent attack. I have been told that rats will not attack PVC because they can't stand the taste. An expert plumber told me that there is an insulating material for PEX which repels rats. – Jim Stewart Dec 31 '20 at 11:52
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    Im just going to hit the easy button and remove the bathroom window and add a piping chase. I have the same thing in my current house. no big deal. – Tony Dec 31 '20 at 17:37

There is a reason why nearly all "plumbing walls" are located in the interior of the house, in a non-load-bearing wall. This is the reason.

You've got a bearing citrus tree, and you're talking about exterior 2x4 walls, so I'm going to assume that you're in the southern hemisphere in someplace with mild winters. That's relevant, because the applicable codes will likely be different.

Don't bother trying to tie all the vents together by going sideways in the the wall. Instead, tie the close ones together, and then try to get the rest together in the attic space. It looks like the tub and toilet vents could merge and go right in the photo. You might want to add another solid stud in the right-side gap right of the window, after installing the vertical vent.

  • Yes in Houston. In an attempt to make this easier and meet code. Could I tie the toilet and sink vents together (looping vent around king/jack stud) and then going to attic to tie into rest? i keep hearing i cant drill that big of hole or shouldnt drill thru the king/jack window framing. Then move the right hand window frame to left side of bathtub so i have clear shot for tub drain to attic. hopefully that makes sense. – Tony Dec 31 '20 at 14:20
  • Ah, Houston. Where they don't believe in zoning. (I remember a stripmall with a liquor store, a Baptist church, a massage parlor, and an asian restaurant all jammed together). It's not the southern hemisphere, but does explain the citrus and thin walls. Make note of the sizes of vent required for each drain, and the step-up in size when you merge two or more vents. Then maybe cheat. Also, be aware of places where venting is not required. Things like "required if more than X distance" also mean "not required if less than X distance". – aghast Dec 31 '20 at 18:43
  • You haven't said what you're doing on the outside of the building. You might consider, as someone suggested, promoting the bathroom walls to 2x6 instead of 2x4. That might give you enough thickness to drill through. Or kick some of the vents out through the wall, and merge them together outside. (Ugly, but you might be able to cover it on the outside.) – aghast Dec 31 '20 at 18:45

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