Options for locating a toilet ~12 feet from stack

[triangular]

So, I live in a three-family condo above two other units. The others were initially fine with my renovation.

I had a licensed experienced plumber come and write up a plan that would involve a second soil stack straight downward from the new fixtures, then across the basement ceiling to meet the existing one. This would involve an exposed 3" pipe in a corner of the other units' closets, which they could tie into for later renovations, and which one owner was looking forward to doing.

Then the other owners decided they were not OK with an exposed pipe, nor with anything that would involve anyone entering their unit whatsoever. They are OK with anything else I do, including doing anything to the basement, putting a vent out the roof, exhaust fan out the side wall, etc. -- I just cannot touch their unit whatsoever.

The wall studs are a little over 4" (1800s house) so we could potentially put the drain pipe in the wall, but would have to drill from above and below since we can't open up a wall whatsoever in one unit (other unit is fine with opening their wall), and there is possibly a piece of fireblocking halfway down the wall cavity (some of our walls have it, some don't). This would be a huge pain in the ass, but I will do it if I can find someone locally who does this kind of thing.

Other thought is whether the drain could be run across the floor to meet up with the existing stack. The joists are about 8 inches deep, so we'd have the slope, and I think we are OK with notching joists since we'd be in the lower part of them once we get there (joists run horizontal in this photo/most of the run would be parallel). Is this permissible if we vent it straight up from the new location? Obviously it would be a lot of annoying demo, but I am wanting to see what my options are.

Feel free to let me know about anything else I may have incorrect or have overlooked; I'm a carpenter, not a plumber whatsoever.

 

[John Gayewski]

Can you drain into a sump pit and pump it overhead? Notching 2x8's ain't gonna work unless your have a system to fix them.

 

[Sponsor]

 

[triangular]

I do know how to attach steel reinforcers to joists. That's what's typically done in these houses. They're not a modern 2x8 BTW; they measure a bit over 8 inches.

Doesn't code prohibit Saniflo and similar unless below grade? That was my initial thought, but plumbers are telling me they can only be approved when there's no way to drain via gravity. Or is there a loophole you're aware of?

 

[John Gayewski]

If there's a way for you to drill the joists with slope and insert the pipe between them and fix the joists then you should do that. If no then it sounds like it may need pumped.

Maybe you don't need a saniflo. Maybe a sump pit would work. There's not really a way for me to tell you what will work from iowa.

 

[triangular]

If there's a way for you to drill the joists with slope and insert the pipe between them and fix the joists then you should do that. If no then it sounds like it may need pumped.

Maybe you don't need a saniflo. Maybe a sump pit would work. There's not really a way for me to tell you what will work from iowa.

Yes, as I explained, I can get proper slope, but wasn't sure if it can be this far away from the stack. Things I'm reading say no, but that seems to be assuming they also can't put in a vent. I can put in a roof vent right where the toilet is. Does that then make it OK to be this far from the drain stack?

Where are you thinking I would put a sump pit? Don't those go in basements? Are you talking like an ejector pump? AFAIK, none of that is allowed unless it's required due to being below grade.

 

[John Gayewski]

A 3" trap arm can be vented 12' from its trap. Doesn't your drawing show interior walls? A vent can go up any wall through the joists and tie in anywhere.