Adding standpipe to vented shower run

After laying out my shower drain run I got the bright idea that I could easily splice in a washer standpipe for the garage, through the band joist.

I stubbed together the layout below to illustrate my question. The section on the far right is for my proposed washing maching standpipe and P-trap outside, but if this is a "no go" I'll remove it altogether.



This 2" run would connect through the lower Y to the 3" vertical stack, below the toilet described here:
https://terrylove.com/forums/showthread.php?t=31332
BTW the SanT on its back for the shower vent is just for this illustration, I don't have the SanY + 1/8 bend right now.

As always, thanks in advance for your attention,
Charles

Jeez, here's the pic

Sorry, I didn't mean to post that. I had trouble getting the picture to embed.
I hope this works.

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After laying out my shower drain run I got a bright idea (actually, my buddy's wife suggested it -- I'll take any blame, though) I could easily splice in a washer standpipe for the garage, through the band joist.

I stubbed together the layout below to illustrate my question. The section on the far right is for my proposed washing maching standpipe, but if this is a "no go" I'll remove it altogether.



This 2" run would connect through the lower Y to the 3" vertical stack, below the toilet described here: https://terrylove.com/forums/showthread.php?t=31332


BTW the SanT on its back for the shower vent is just for this illustration, I don't have the SanY + 1/8 bend right now.

As always, thanks in advance,
Charles

It's fine and as long as the san tee for the vent is dry above it's fine also.

drain

The way you have it assembled it looks like the washer trap would be below the floor. That is usually a bad idea for several reasons, one being that the standpipe would exceed the maximum allowed by most codes. Your idea is okay, the execution might use some cleaning up.

Thanks!

Thanks nhmaster & HJ,

Very reassuring!

nhmaster: The 1-1/2" vent for the shower is dry and comes off at 45° from horizontal, I'll review my understanding of when that's appropriate for a horizontal run.

HJ: The 2" piece for the standpipe P-trap will emerge through the band joist at 17-18" above the garage floor. I think that puts it in the sweet spot.

Your idea is okay, the execution might use some cleaning up.

Click to expand...

This is the best time for me to improve that! Do you mean like running the whole thing more horizontally?

The arrangement below raises some havoc with the shower vent connecting at no less than 45°, shoving everything over and down some, but can be pursued.


LOL, So far the only improvements I come up with are:
-- Show some "meat" showing between joints in case of future cutoff
-- Remove unsightly price tags

Again, Thanks lots,
Charles

drain

How long will the riser be, and how high above the floor? Using your shower drain as a reference for the "P" trap location, it looks like it will be much too low.

drain

The shower drain will only be 12" above the P-trap. The pipe in the picture was just an odd piece I stuck in to show that something goes up.

The floor level is actually at the very top of the final 1/8 bends of the vents. My garage is about 24" lower than the bath floor.