Drain slope on new toilet run

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pplank

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First off, thanks for any and all help in advance. Quick back story, my wife and I bought my godparents 1910 homestead/ farmhouse and are in the process of gutting and remodeling the second floor as the first floor was done back in the mid 90's. The first floor includes a new addition and two new bathrooms. They both have PVC plumbing that was coupled to a 4" cast iron soil stack that transitioned into the 4" vent stack through the attic and roof. I've gutted the second floor bathroom and am relocating all plumbing fixtures. My issue that I need help with is the toilet run. Where I'm placing the toilet is about that 2' - 2 1/2' from the soil stack and about 4 1/2 - 5' from the vent stack. With the toilet so close to the soil stack, what kind of slope should I be trying for to get it to drain properly? I've tried the 1/4 off bubble, but that seems a bit to steep, and 1/8 off bubble doesn't look right either. I've two runs set up to experiment with. The first is a 3" that transitions up to the 4" at the soil stack, and the second is a full 4" run. My second question would be the venting of the toilet itself. Would it be possible to use the same drain line as a wet vent since the actual vent line is so close? Oh and before anyone comments, I didn't cut the joists. I'm guessing they did that when they brought the plumbing into the house way back in the day.

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1/4” of slope for every 1’ of grade. Also, what is the plan with that tee down from the toilet flange. You cannot use a fitting in that manner.

You will want to wet vent the toilet off the basin or shower drain. Just make sure the wet vented section is 2”
 
I'm guessing that T fitting might work if turned around? But even then it looks like waste might try to head in the direction of the vent.

Here in Cali seems ABS is much more common for sewer lines than PVC though I gather that the latter is allowable. I've read up a bit on the pros and cons but what I don't get is why there seem to be regional preferences.
 
The only way you can use that tee is the toilet waste enters the curved part and drops down
 
The tee in the pic is sitting right next to the soil stack that runs aprox 12' to the basement and then exits the house. I don't have it connected yet. I tried a double wye fitting, but it was jsut too big and wouldn't fit low enough to be able to lay the new subfloor, that's why I went with the tee. waste will leave the toilet, run for about 2 1/2' and then drop straight down to exit the house. On the other side I'll have the shower drian line connected right before the vent stack. It'll drian to the other side of the tee as will the vanity and the tub.
 
That's a sure fire way to 100% straight F up your entire renovation. Forget about the slope issue. Using the tee in that manner will just cause you a lifetime of clogs and headaches.

Post a picture or diagram of the bathroom layout and placement of the stack, then we can come up with something that will work
 
It doesn't matter you can't use the Tee in the manner that you want to use it. You're going to spend all this money on doing the renovation and then not do this one thing correctly that's going to lead to problems in the future which then you'll have to spend even more money to fix.
 
You might have to put the toilet where it will work.

what's below?

One thing nobody mentioned was you can make the vent 2"
it's okay to increase vent when you tie it back into the exiting 3' or 4" existing vent.

need more pictures of what is below where stack is going down.

Toilet waste arm can be 3"

Vent has to be vertical. 45 degrees or more from horizontal, so that horizontal section does not get fouled
 
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Attached are more pics of my project. They drawing is not to scale, of course, and when I uploaded the pics they were all oriented correctly. Pic 1 is self-explanitory. 2) is the pic of our living room. It was asked what was belwo the toilet. 3) is a pic of the soil stack going through a wall in our living room. It's a wall for double pocket doors. 4) again self'explanitory. 5) is looking down the soil stack as it leaves the bathroom. 6) anoth pic of the soil stack. 7) is the proposed layout of the remaining connections from the vent/shower/tub. I do realize that the wye is backwards.

The concensue appears to be that I can't use the tee the way that I intend. It's been suggested that I may need to reposition the toilet, but I feel that i would have the same issue as most of you all have brought up, a clogged line.

What type of fitting should I be using? I'm at a loss.

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I’d like to help but you have to many things wrong with this project.
 
I would suggest getting a licensed plumber in there and try and get a layout that works. You said you are changing the fixture layout. That is probably why the original layout was the way it was.
 
I'm having a hard time following your pictures and plans. I respect the willingness to go DIY, I'm in the middle of something now myself, but it's sobering how bad you can screw up and how much it will cost to fix it.

Plumbers don't have large liability policies by accident. When things go wrong, or were done wrong, it's costly to fix.

I was originally a carpenter, moving to mostly finish in recent decades and you can often fake your way through rough spots, IOW, something in the framing was funky but you can figure a way to fool the eye well enough to make it all look good. I've learned the hard way that you can't fake plumbing.

Who knows, maybe you could find someone as a consultant, to help you lay things out in person. I've known small general contractors who would do that, would show up after their main work and put in an hour or two of supervision.
 
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Well, not exactlly what I was hoping for, but it is what it is. The original layout was 12' long x 5' wide with the narrowest part being 3' wide between the tub and sink/toilet. In the diagram, the vanity is setting where the tub was. Right in the middle of the room was the sink and to the right of the sink on a platform was the toilet. It was basiclly setting in front of ther window. Like I mentioned in my original post, it was all 4" cast iron from the roof to the basement. The reason that the toilet was on a platform was it immediatly came out into a cast iron 45 degree to another 45 degree into the soil stack and the tub and sink were plumbed in them. We since took out that wall to expand the bathroom, hence the layout change. Since I was not really getting the info that I was looking for, I have contacted several plumbers in my area and will have them do the rough-in portion. Thanks
 
Well, not exactlly what I was hoping for, but it is what it is. The original layout was 12' long x 5' wide with the narrowest part being 3' wide between the tub and sink/toilet. In the diagram, the vanity is setting where the tub was. Right in the middle of the room was the sink and to the right of the sink on a platform was the toilet. It was basiclly setting in front of ther window. Like I mentioned in my original post, it was all 4" cast iron from the roof to the basement. The reason that the toilet was on a platform was it immediatly came out into a cast iron 45 degree to another 45 degree into the soil stack and the tub and sink were plumbed in them. We since took out that wall to expand the bathroom, hence the layout change. Since I was not really getting the info that I was looking for, I have contacted several plumbers in my area and will have them do the rough-in portion. Thanks

Sounds like a good plan. Will probably be a good education. I've learned a lot about basic theory by observing the work plumbers have put in on various jobs I've been on. You can still save money by doing a lot of the hookups and fixture installation yourself.
 
You might have to put the toilet where it will work.

what's below?

One thing nobody mentioned was you can make the vent 2"
it's okay to increase vent when you tie it back into the exiting 3' or 4" existing vent.
Not if it’s the main stack. Which it probably is which is why it’s 3” continuing through the roof. That is code in Canada at least
 
Seems like you need more vents. All that plumbing running into a 3” stack vented further back seems that you’ll have major issues.

Why not run a vent up from the double vanity, on the other stuff you need a better layout.

In all trades plumbing seems to be the trickiest, knowing how to vent, flow rates and to do it all by code.

Call a few contractors, have them give you an estimate and walk through with them the options . They’ll probably tell you what you need to do
 

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