Pipe layout to move closet flange a few inches

[Pghsebring]

I have to move the closet flange about 1.5" closer to the wall and as close to 3" to the left as possible - back when they built the house they didn't do a good job getting it close enough to the wall. It is 3" cast iron and there is another drain line 2" to the left of it (the direction I need to move it). The centerline of the 3" horizontal pipe is ~13" below the new finished floor. The plan is to cut the cast iron 2" from the bell and use a shielded fernco with 3" PVC to start. (I have tried getting CI out of a bell before and I want no parts of that ever again - I'll cut it with a CI blade on my sawzall instead.)

I can come up with 20 plans in my head of how to get from my CI stub to the floor - use 3" or 3" x 4" elbows angled 22 or 45 deg, 3" x 4" reducers, 3" the whole way, use 22 or 45 hub x hub or street, etc, etc, etc. I am asking in your experience, if you start about 13" below finished level with your 3" CI, what is your combination of PVC parts that gets you moved over to the left 3" (while avoiding that other drain) and also 1.5" closer to the wall (that's the easy part) that is least likely to clog later (and fit in my space)?

We are aiming for the red laser perpendicular to the wall to the be centerline of the closet flange.

 

[Reach4]

How far down is that cast iron?

A Sioux Chief 889-GPOM might have been just the ticket if that were 4 inch cast iron instead of 3.

https://www.supplyhouse.com/Sioux-Chief-889-GPOM-4-Inside-Push-Tite-Offset-Closet-Flange-w-Stainless-Steel-Ring-Full-Flush-1-1-2-Offset

If you could expand the cast to 4 inch lower, that could potentially work, but that is unlikely.

A Code Blue 3 inch offset outside compression flange only offsets by 1 inch.

There are a lot of glued offset closet flanges that offset by 1.5 inches if you have enough vertical space to convert to plastic (PVC or ABS versions available).

 

[Sponsor]

 

[Pghsebring]

How far down is that cast iron?

A Sioux Chief 889-GPOM might have been just the ticket if that were 4 inch cast iron instead of 3.

https://www.supplyhouse.com/Sioux-Chief-889-GPOM-4-Inside-Push-Tite-Offset-Closet-Flange-w-Stainless-Steel-Ring-Full-Flush-1-1-2-Offset

If you could expand the cast to 4 inch lower, that could potentially work, but that is unlikely.

A Code Blue 3 inch offset outside compression flange only offsets by 1 inch.

There are a lot of glued offset closet flanges that offset by 1.5 inches if you have enough vertical space to convert to plastic (PVC or ABS versions available).

The top of the horizontal drain is about 11.25” below the new finished floor and the centerline is about 13” below the new finished floor. I looked at offset flanges but I need to go 1.5” closer to the wall and 3” left for about 3-3/8” total on the diagonal. Thats why i figure ill have to cut that 3” horizontal drain and start from there with a shielded fernco.

 

[Reach4]

There are also good 45 degree plastic flanges, if that helps. I figure those take more skill to get right.

See https://terrylove.com/forums/index.php?threads/fernco-couplers.95922/ for discussions of which couplings are rated for underground.

 

[wwhitney]

Per Charlotte Pipe's catalog:

A plastic 3" quarter bend (to use as a closet bend) has a run of 3-1/16" in each leg, while a plastic 3" street 1/8 bend (45 degrees) has a run of 3-1/4" in the street leg. So if you use those two fittings, with the quarter bend rolled 45 degrees, to do an offset to the left, you'd travel (3-1/16+3-1/4)*sin(45 deg) = 4.5" to left.

Assuming that's too much, you could try a street 1/16 bend (22.5 degrees) instead of the 1/8 bend. It has a run in the street leg of 2-5/16". So if you use it with the quarter bend rolled 22.5 degrees, you'd travel (3-1/16 + 2-5/16) * sin(22.5 deg) = 2" to the left.

Assuming that's too little, to get 3" to the left you'd need a total run at 22.5 degrees of 3/sin(22.5 deg) = 7.84". That's feasible with a regular 1/16 bend, it has a run (excluding socket) of 13/16", so you'd need a short pipe segment of 7.84" - (3-1/16" + 13/16") = 4", which is long enough to have full engagement in both sockets, which are 1.5" deep. I.e. the hubs on the two fittings would not clash but would be 1" apart.

The total rise from doing that would be 7.84" * cos(22.5 deg) plus 13/16" run from the leg of the 1/16 bend. That makes 8", which is the rise from the center line of the 3" horizontal fixture drain to the bottom of the socket on the 1/16 bend; the socket is 1.5" deep, so it would 9.5" to the top of the socket. That leaves you with 3.5" to your finish floor, so would work with any 3" hub closet flange that extends no more than 3.5" below the floor. E.g. Sioux chief 884, which extends 2.4" below the floor, meaning you could use a 5" or so piece of pipe with 1" showing (after installation, if you had a way to see it) between the two hubs.

I suggest getting the actual fittings on hand and checking the spatial arrangement, rather than relying on my having read the correct dimensions from the catalog and done the correct math.

Cheers, Wayne

 

[Pghsebring]

Per Charlotte Pipe's catalog:

A plastic 3" quarter bend (to use as a closet bend) has a run of 3-1/16" in each leg, while a plastic 3" street 1/8 bend (45 degrees) has a run of 3-1/4" in the street leg. So if you use those two fittings, with the quarter bend rolled 45 degrees, to do an offset to the left, you'd travel (3-1/16+3-1/4)*sin(45 deg) = 4.5" to left.

Assuming that's too much, you could try a street 1/16 bend (22.5 degrees) instead of the 1/8 bend. It has a run in the street leg of 2-5/16". So if you use it with the quarter bend rolled 22.5 degrees, you'd travel (3-1/16 + 2-5/16) * sin(22.5 deg) = 2" to the left.

Assuming that's too little, to get 3" to the left you'd need a total run at 22.5 degrees of 3/sin(22.5 deg) = 7.84". That's feasible with a regular 1/16 bend, it has a run (excluding socket) of 13/16", so you'd need a short pipe segment of 7.84" - (3-1/16" + 13/16") = 4", which is long enough to have full engagement in both sockets, which are 1.5" deep. I.e. the hubs on the two fittings would not clash but would be 1" apart.

The total rise from doing that would be 7.84" * cos(22.5 deg) plus 13/16" run from the leg of the 1/16 bend. That makes 8", which is the rise from the center line of the 3" horizontal fixture drain to the bottom of the socket on the 1/16 bend; the socket is 1.5" deep, so it would 9.5" to the top of the socket. That leaves you with 3.5" to your finish floor, so would work with any 3" hub closet flange that extends no more than 3.5" below the floor. E.g. Sioux chief 884, which extends 2.4" below the floor, meaning you could use a 5" or so piece of pipe with 1" showing (after installation, if you had a way to see it) between the two hubs.

I suggest getting the actual fittings on hand and checking the spatial arrangement, rather than relying on my having read the correct dimensions from the catalog and done the correct math.

Cheers, Wayne

Ok sounds good, ill get the 22.5 and mock that path up. I was concerned with the 22.5 i might run out of vertical space and it does seem close! I could always do the street and move it only 2”, it would just make the toilet area a little smaller (but still well over code.)

 

[Pghsebring]

There are also good 45 degree plastic flanges, if that helps. I figure those take more skill to get right.

See https://terrylove.com/forums/index.php?threads/fernco-couplers.95922/ for discussions of which couplings are rated for underground.

I see that only the husky 4000 is approved for this so i found one at my local ferguson. Thank you for that.