Proposed Drain Change: Is This OK?

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Bird Doo Head

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Hello Everyone!

There is a drain pipe (is Soil Pipe the correct term?) which runs well below the floor joists in my basement. I've been bashing into it for years. I have the opportunity to move it up, into the joist bay. (I'm replacing the floor in the bathroom upstairs.)

The pipe is from a toilet and it ends in a 3x3x3x1 1/2" fitting on a stack. As it exists, the closet flange has a pipe going through the floor & into a 90 degree elbow. Then, a pipe runs about 60" to the 3x3x3x1 1/2". All fittings above ground are Schedule 40 PVC.

My "Great Idea" is to use a toilet flange that fits into a 3" Schedule 40 pipe and use a street 90 directly into the flange. I'd travel along in the bay for about 38" and connect it to two 45 degree bends that are connected by a short length and rolled into position. The lower 45 will be attached to a short stub of pipe left at the "tree" when I cut out the old. I messed around with some scraps & fittings. Physically, it works and I can pitch the horizontal 1/4" p/ft.

I can't describe it very well, so I put a drawing of "Existing" & "Proposed".

The question is: If I'm using two 45 degree angles will the water run away, leaving the debris behind? What do all of you think?

Thanks for your help!
Paul
PS: Is 1/4" per foot the correct pitch for the horizontal run?

Front Bath WC Drain Proposal.jpg
 
Mreh...I personally wouldn't use such a setup.

Right off the bat, you are suggesting using the smallest flange size available, then immediately cramming it into a street 90, which will reduce your flow immensely. On three inch pipe, a short 90 is equivalent to 11 feet of straight pipe (a street elbow is closer to 15 or so I can't remember the exact number) and that isn't taking into consideration that the pipe will also be handling solids, or the fact that it will be crammed right up against the toilet.

The dual 45s themselves shouldn't cause much issue, really. Together they will restrict flow about as much as 8' of straight pipe and shouldn't cause any buildup at the seams if attached properly.
 
If the 45's are off set to raise the closet bend as in my crude picture,
Red the origanal line that was cut out and Black being the finished product,
The answer is NO

The horizontal line has to remain horizontal until it connects to a vent.
You would have to raise the Tee.

You restrict the out flow with the flange you discribed
Use a street 90 with a flange that glues onto rather than inside.

Untitled.jpg
 
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Thank you both for your kind assistance.
I'm glad I passed the idea by the pros first!
Raising the tee can't be done without lots of 'in the wall upstairs' work, so I think i'll just leave it as it is & learn to duck.
Thanks Again,
Paul
 
I might be wrong!
What I said is true for a trap arm from a fixture p-trap.
The weir of a water closet water seal is different.

I just looked it up in an old code book

" The vent pipe opening from a soil or waste pipe Except for water closets and similar fixtures, shall not be below the weir of the trap."
 
Thank You Mr. David!

That being said, and after some re-measuring, I (think) I can even raise the tee enough that the two 45 degree ells at the stack can be very close for a short offset (maybe even 45 & street). - If it helps.

I do have a couple of alternative ideas for the street 90 immediately after the toilet to ask about, if you all don't mind-
How far below the flange is a good distance before the bend?
Would a long sweep ell be better than the street 90 I first suggested?
Would two 45 degree bends be even better below the toilet outlet?

Thanks very much!
Paul
 
They make a 4" street X 3" hub closet bend that will take a standard 4" hub closet flange
You don't need to extend the drop into the 90 at all .
You can put a 1" or 2" block of wood between the underside of the floor sheathing and the top of the horizontal
pipe. This will prevent you from pulling it up.
 
Hi Mr David
Thanks for the information!

If I understand correctly, the block of wood is to keep the flange from lifting from above. It is used as opposed to screwing the flange to the subfloor. (Or in addition to screwing it to the subfloor.) Did I get it correct?

I'm not quite clear on the concept of the 4 x 3 ell. By using the word "hub", does that mean that the ell & flange are cast iron no hub style & connected with a no-hub coupling? Or is it PVC with "female" hub on the ell and the flange glues into the socket on the ell?

Sorry I didn't understand the reply. I think my brain is stuck in the Huh? What? mode this morning.

Thanks!
Paul
 

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