[rtoni]

I have a main drain (septic) that comes into crawl space thru wall @ 10 in off the ground and @30 in under the joists My stack drops thru floor @ 3ft off to the side of the drain axis. So I have to offset the stack over to the drain and then tie it in. I would prefer to keep the offset for the stack tucked right under the joists (so its tucked up out of the way - it's right beside my access). Which means my stack will turn 90 deg towards the main drain, run @ 3ft to where it reaches (crosses above) the main, then 90 deg down to tie into it.

Is this acceptable?
Can I just use standard 90 deg elbows for the 2 bends in the offset (across and down)?
How do i tie the last short "down" section of the stack offset into the drain? I'd like to drop the stack into a tee or a wye at this point as opposed to another elbow as i could then add a clean out right in the end os the drain. Does this make sense?

 

[plumber666]

Makes sense, but never use 90's when you're going from vertical to horizontal, only from horizontal to vertical. And use 45's for any lateral offsets. When you tie back in to the septic line out, use a wye for a cleanout.

 

[rtoni]

thanks plumber666 - appreciate the prompt response.

so this means (apologies if I'm a bit slow on the uptake):

- I could use a couple of 45's where the stack initially turns (from the vertical into to the horizontal offset) - no 90 allowed here
- then I can use one 90 where my offset turns downs again (horizontal to vertical)
- then a wye to tie this short vertical run into the drain (with a cleanout)

would it make more sense to use a wye + 45 at the first bend (instead of 2 x 45's) - just gives me another access point to clean out (admittedly, it's just the short run across the offset, but could it hurt?)

I hope i have this right. the help and patience are appreciated.

 

[plumber666]

More is better with cleanouts. You're totally on the right track, and obviously in touch with your "inner plumber".