Toilet Drain Pipe Around Joists

[sberg74]

I am looking to move a toilet on a bungalow main floor. Currently the drain sits 1' from the stack and drops straight into a double 45 wye that's about 5 1/2 feet off the basement floor.

New toilet location is about 4 1/2 feet away, as the crow flies, but does not have a clear path through the joists and main cross beam (used to be a 32/32 shower). It's a 6' run if I go parallel to the joists and then turn toward the stack. This all seems doable with respect to venting.

The problem is I can't keep a proper 1/4 slope, if I try to line it up with the existing wye. Ideally, I wouldn't want to touch the stack and would re-use the existing wye.

Options I can think of (see attached image/link):
1 - run 4' with 1/4 slope, parallel to joists, and then drop 6" AND turn 90 degrees with a few 45 elbows, into a 2' run with a 1/4 slope before it hits the 45 of the wye. Really unsure if you can/should even do vertical drops mid run??
or
2 - run 4 1/2 feet with a 6" drop, straight from the main structural beam (try to go as direct as possible).
or
3 - add a new single wye lower down on the stack so I can do 45 from height of the joists down to the middle of the stack (this increases the length of the run a bit to 8')

Suggestions?

Thanks in advance!

 

[Terry]

The toilet can be 6 feet of piping from the stack where it's vented. It can be plumbed at any angle there.

 

[Sponsor]

 

[sberg74]

The toilet can be 6 feet of piping from the stack where it's vented. It can be plumbed at any angle there.

Thanks Terry.

By "any angle" does that mean that I can ignore the 1/4 slope, because it's a short run?

 

[Terry]

A toilet is designed to siphon, therefore the 1/4" rule isn't followed.
Other fixtures that use a vent to "break" the siphon need the rule.

 

[Reach4]

By "any angle" does that mean that I can ignore the 1/4 slope, because it's a short run?

You would still need at least that. Dead level is not good enough.

 

[sberg74]

My concern is too much slope, since I have to angle around the joists. Liquids moving faster than solids. 4 foot run with a 6 inch drop isn't recommended, from what I can tell.

 

[Terry]

The toilet can be run at a 2% grade ( 1/4" per foot ) or at more of an angle. It's the only fixture you can do what with on the trap arm. At a 45 degree angle, you considered vertical anyway.

 

[sberg74]

Ok, got it. Sounds like a combination of:
- short run distance
- venting using the stack (which means the run from flange to stack is the trap arm)
- syphon action

... means I can pick option 2 and just go direct to existing wye... even at a 6" drop over 4 1/2 feet.

Cheers!

 

[Reach4]

- venting using the stack (which means the run from flange to stack is the trap arm)
- syphon action

The trap is within the toilet itself, so no trap arm. The toilet needs siphoning to work. The toilet refills the trap as it fills the tank.

You imagine a slope of about 6 degrees from horizontal. It takes more than one fitting to do that with available fittings.