My father-in-law and I are putting in a half bath on the main floor. The problem is, the location is too far from the main stack, about 15 feet or more. The idea we came up with (see image) is to tie into the sewer line (1) close to where it comes in from the outside. We would have to break into the concrete floor of the basement and tie in as close to the wall as possible. Our new stack (2) would go up into the wall of the main floor where the bathroom will be. It would loop inside the wall and come back down just under the floor. It would then run along the basement ceiling and vent in to the original main stack. The toilet (3) and sink (4) would tie in as shown.

My question is: will this work? If not, can you give me any ideas to make it work?

Thanks in advance...

What do you see as the purpose of looping up and then down with your stack?

What do you see as the purpose of looping up and then down with your stack?

A belated April Fool's joke?

I would take a 3" pvc pipe to the toilet and the stub up at the floor under the toilet would be 4" if I had room to put a 4" x 3" closet bend. About 2 to 5 feet from the toilet I would put a 3" x 1 1/2" combination [wye and 1/8 bend] to pick up the lavatory with sweeps going all the way and a 1/4 bend stubbing out. Then under the vanity I would use a 1 1/2" sanitary tee and a master trap and a studor vent. This would complete my pvc drain piping except for the 4" sanitary tee and a master trap and a studor vent. this would complete my pvc drain piping except for the 4" floor flange for the toilet.

i would take a 3" pvc pipe to the toilet and the stub up at the floor under the toilet would be 4" if i had room to put a 4" x 3" closet bend. about 2 to 5 feet from the toilet i would put a 3" x 1 1/2" combination [wye and 1/8 bend] to pick up the lavatory with sweeps going all the way and a 1/4 bend stubbing out. then under the vanity i would use a 1 1/2" sanitary tee and a master trap and a studor vent. this would complete my pvc drain piping except for the 4" x 3" floor flange for the toilet.

What, and eliminate the loop altogether?

Where's your sense of fun?

[grinz] I missed April first.

What do you see as the purpose of looping up and then down with your stack?

Thanks for the quick reply...

A plumber I spoke to recommended that I go with this approach, he also mentioned that the peak of the loop be at least 42 inches above the floor. I'm not 100% confident that this is the correct way, hence why I'm seeking your advice. It's also possible that I have misinterpreted what he meant. Are your thoughts that I shouldn't have to include a loop?

I would want to peek at the license of a plumber that gave you that diagram

i would want to peek at the license of a plumber that gave you that diagram

I made the diagram to illustrate what he told me and to show what we're thinking of doing.

So according to your suggestion Doug, not only should I kill the idea of including this loop, but also the idea of running back to the main stack, correct?

My father-in-law and I are putting in a half bath on the main floor. The problem is, the location is too far from the main stack, about 15 feet or more. The idea we came up with (see image) is to tie into the sewer line (1) close to where it comes in from the outside. We would have to break into the concrete floor of the basement and tie in as close to the wall as possible. Our new stack (2) would go up into the wall of the main floor where the bathroom will be. It would loop inside the wall and come back down just under the floor. It would then run along the basement ceiling and vent in to the original main stack. The toilet (3) and sink (4) would tie in as shown.

My question is: will this work? If not, can you give me any ideas to make it work?

thanks in advance...

My Dad,(rest his soul) used to call a latout like this one "a abortion". You have installed a "s" trap on the lavatory and a halfassed attempt at a island loop vent, that when you follow it out it connects to the vent stack forming a trap. Hey guys! Stop me if I'm wrong here, but I've always been told that vents pitch back to the drain. Looking at the drawing all can see is a trap to collect moisture and water until it blocks the horizontal line. When I first saw this drawing, my first thought was, "what's wrong wity this picture?" And then I snapped to the answer. Everything!!
Regards, Tom

My Dad,(rest his soul) used to call a latout like this one "a abortion". You have installed a "s" trap on the lavatory and a halfassed attempt at a island loop vent, that when you follow it out it connects to the vent stack forming a trap. Hey guys!! Stop me if I'm wrong here, but I've always been told that vents pitch back to the drain. Looking at the drawing all can see is a trap to collect moisture and water untill it blocks the horizontal line. When I first saw this drawing, my first thought was, "what's wrong wity this picture?" And then I snapped to the answer. EVERTHING!!!
Regards, Tom

Thanks.

I think (hope) that this is just a matter of having misinterpreted the Plumbers suggestion.

Run Doug's suggested lay-out by the Plumber and see what he thinks.

I think (hope) that this is just a matter of having misinterpreted the Plumbers suggestion.

Run Doug's suggested lay-out by the Plumber and see what he thinks.


I think that's the route I'm going to go. Just to clarify, in Doug's suggestion, I still need to go into the basement floor and tie into the sewer line from the street, but that's it. I don't need to run a vent over to the main stack as long as I use a studor vent. Right?

I think that's the route I'm going to go. Just to clarify, in Doug's suggestion, I still need to go into the basement floor and tie into the sewer line from the street, but that's it. I don't need to run a vent over to the main stack as long as I use a studor vent. right?

That was my take on his suggestion.

[grinz]
Tom, they changed the code last year. You can do whatever you want with a vent so long as water can not get trapped in it.
[i know, sloppy]

[grinz]
tom, they changed the code last year. you can do whatever ya want with a vent so long as water can not get trapped in it.
[i know, sloppy]

The only time I bother to grade a vent is if I'm flat-venting below the flood rim of the fixture.

Anything horizontal above the flood rim is run flat.