Reconfiguring this Drain

[Cboneill0099]

Hey Everyone - Hoping to get some advice on properly reconfiguring this gem the previous homeowner left me with. You can see how bad it pitches the wrong way. I called a plumber, but was quoted $1,800 and I don't have that kind of money for this repair, so I'm hoping to get this done myself.

The piece I have marked as eliminating was a drain from an old sink that was removed. The vertical 4" cast iron pipe is coming down from the second floor and is the drain for a shower, two toilets, and three sinks. That runs into the 45/wye and to the 4" cast iron that goes outside. The 3" pipe is the drain from my kitchen sink and is also connected to a vent going to the roof.

Hoping to get advice on how to properly do this. This is what I was thinking:
1) Cut the 3" prior to the coupling where I have it marked.
2) Starting from the cast iron coming out of the block. Connect 4" PVC (with a fernco?) and run that into a combo fitting (rather than the wye/45 as pictured?).
3) A 4" pipe coming out of the top of the combo connecting to the cast iron going to the second floor (with a fernco?). Cut this the proper length to get 1/4" per ft pitch on the drain going to the street?
4) Replace the 3" pipe the way it currently is? That seems to be correct.

Appreciate any advice on this.

 

[Reach4]

Is the pipe that is sloping the wrong way the horizontal on IMG_5909.jpeg? Can you just cut out the right-side lower elbow, and raise that end? That elbow should have been a long sweep anyway.

For the "eliminating" maybe cut the pipe a little above the X and glue on a cap. That way it is available if you want another drain input some day.



O

 

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[Cboneill0099]

Is the pipe that is sloping the wrong way the horizontal on IMG_5909.jpeg? Can you just cut out the right-side lower elbow, and raise that end? That elbow should have been a long sweep anyway.

For the "eliminating" maybe cut the pipe a little above the X and glue on a cap. That way it is available if you want another drain input some day.



O

That’s correct. That’s the pipe sloping the wrong way. I can cut out that elbow for sure. I don’t think I can raise that end because the vertical pipe coming out of the wye into the cast iron would block me.

Do you think I’m overcomplicating this? Perhaps I can cut that stub going into the vertical cast iron short enough so I can raise that horizontal run up so it’s pitched correctly?

 

[wwhitney]

A few comments:

- I'm not following what the geometry above the Fernco is in on the 2nd floor drain in the 2nd photo. But I gather it's cast iron, and I'm not sure the geometry above the Fernco matters.

- Those Ferncos are only for use underground. They should be replaced with shielded rubber couplings, e.g. Fernco Proflex.

- Can you tell if the weight of the 2nd floor drain is properly supported within the crawlspace? As a guess, it looks like the slope on the horizontal 3" drain in the first picture is more that typical. So it is possible that the PVC 4" line was properly sloped when installed, but the weight of the 4" cast iron pushed it down over time, dragging that horizontal 3" line along with it. If that's the case, not sure how you'd lift the cast iron back up, or if you'd need to, nor am I sure how you'd check the 2nd floor to see if there's any problems with the DWV caused by the cast iron stack dropping.

- If you determine the cast iron is in the correct place vertically, and is properly supported, and all you want to do is fix the misslope on the 4" PVC line, I would suggest removing the two Ferncos and cutting the vertical 3" PVC segment, after ensuring the PVC above your cut is properly secured. That separates out a region of pipe and fittings.

The now loose region can be reconnected with (3) Fernco proflex fittings of the proper size and type. You can adjust the slope of the the horizontal 4" pipe within that region by cutting shorter the 4" riser in the middle as well as the 3" riser in the corner.

Hopefully the pipe ends within the current horizontal Fernco are quite close to each other with little gap, as the Proflex fitting is shorter and so will handle only a small gap. If you do have too large a gap there you'd need to redo a fair amount of the PVC to remove that gap. (Or you could try using a Fernco 1056-44RC, which is the same length as the Fernco in the photo but has extra shielding; that's still technically only allowed underground, though.) Perhaps you can check before starting any disassembly what the gap is, by feeling for the pipe edges through the rubber.

- I didn't mention the drain to be eliminated yet, but cutting and capping the vertical riser on it seems obvious. I would suggest a solvent weld cap, and leaving enough intact pipe between the last fitting and the cap so that in the future you could cut the cap off and make a new connection to the riser.

Cheers, Wayne

 

[Reach4]

That’s correct. That’s the pipe sloping the wrong way. I can cut out that elbow for sure. I don’t think I can raise that end because the vertical pipe coming out of the wye into the cast iron would block me.

Do you think I’m overcomplicating this? Perhaps I can cut that stub going into the vertical cast iron short enough so I can raise that horizontal run up so it’s pitched correctly?

I think so. You can consider switching the prescribed shielded (metal banded) couplings while you are at it.

Note that you can loosen and slide the metal on the shielded couplings, but you can actually remove the metal, and put it back after the rubber is where you want it if there is not enough room to slide.