First let me THANK All for the feedback and your time.
Let it be known that NONE of these are my drawings. Just some examples I found to help describe the situation.
cacher_chick
The drawings above fail under code, as they show a 1-1/2" wet vent, which is not allowed.
FWIW I'm using a 2 inch wet and dry vent and where it shows 1 1/2 I'm also using a 2 inch.
The san-tee on the horizontal is strictly prohibited except on a DRY vent connection to a horizontal vent (above the flood rim of the highest fixture served). A wye or combo is the only proper fitting for a vent take-off on a horizontal drain.
Will double check SAN-TEE can NOT be used for a dry vent on the horizontal.
Logically -- to me -- this doesn't make sense since whether you use a Y combo to vent vertically from the horizontal or a SAN-TEE,
both are only carrying air.
Add: Look at the bottom Note which supports SAN-TEE use for venting.
https://ibcode.com/uploads/Aug_24_Sanitary_Tee.pdf
The bottom pictures show waste into SAN-TEE and I agree NOT TO CODE.
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Without a vent you CANNOT "DROP" the line into the main line, PERIOD!
Question:
Then how are you supposed to make the connection from the shower to the 3 inch line ?
Some how some where the 2 inch line has to get from the shower drain to the 3 inch branch line
with a "P" trap in the line.
I am not sure WHY you posted the "P" trap drawings because they have little bearing on what you are describing.
Posted to show that with the "P" trap connection to the shower, and that at the "P" trap exit, my only alternatives is some kind of drop to the main (in my case branch) line.
(similar to FIg B as described in Option #1)
FYI, the toilet's "trap weir" is at the poing INSIDE the toilet where the waterway turns downward, NOT in the closet bend
NOTED. As indicated NOT my drawings.
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The floor joists are 3 x 9's. From the bottom of the floor joints to the 3 inch branch line is approx. 10 inches. From the bottom the 3 inch branch line to the concrete
crawl space floor is approx 6 inches. The 3 inch line runs perpendicular to the floor joints.
So as you see I have approx 19 inch crawl space under the joints in which to work. On top of that, this was a solar home that had river rock originally as the crawl
space floor which was flooded with self leveling concrete to fill the voids in the rock to keep the rattlesnakes out. The concrete is NOT level, but has rock BUMPS throughout
on which I have to crawl over or lay on to work. NOTE: This has nothing to do with the plumbing issue other than the difficulty of the working conditions.