Advice on plan to replace basement cast iron drain line with PVC

[Vinmassaro]

I would like to replace 40-50ft portion of cast iron drain pipe in my basement with PVC. It runs along the middle of the wall and makes it difficult to use the space for shelving, storage, etc. There is a kitchen sink on one end and a washing machine drain coming through the basement wall on the other end. Some of the plumbing is not to code, such as the sanitary tee on its back to join the washing machine drain. I would like to cut the copper drain line below the kitchen sink and then turn with a 90 and run PVC drain pipe up high along the ceiling instead, eventually coming down and joining the washing machine drain with a sanitary tee into the vertical pipe, to a wye and 1/8th bend connected to the cast iron pipe with a banded coupling. Some questions:


1. Am I permitted to use 2in PVC? There is only the kitchen sink upstairs and washing machine downstairs draining into this, with a dining room and living space above so no other fixtures could be added in the future.

2. Where should clean outs be added?

3. Would it be better to remove the second to last CI pipe so the CI hub coming out of the concrete could join to the PVC with a compression donut coupling? Or would it be better to cut the CI pipe right after the last hub and join it using a banded coupling?

I attached some photos showing red lines where I want to run the pipe. Thanks!

 

[John Gayewski]

Yes 2in. Use a wye and 8th bend right there the drain comes through the floor and turns horizontal. You then plug the unused portion of the wye for a cleanout.

 

[Sponsor]

 

[Reach4]

That PVC that feeds into the cast iron now should not be feeding into a sanitary tee on its back. Use a 45 or a combo. So while making changes, you should address that.

I do not know if you will have enough elevation of the current horizontal PVC pipe to feed into your new vertical. You might need to feed that waste in at an angle into a separate port in the 3-inch pipe, and that would stick away from the wall. In other words, the output of you old horizontal PVC may not be in the vertical plane with the new vertical.

 

[Jeff H Young]

remove at the first hub at wall insert short piece of 3 inch then a 3 inch combi going up do follow red line. coming out the other side of combi short piece of pipe 3x3x2 wye on horisontal (c/o plug on end ) the 2 inch can take a long sweep on bottom street 1/4 bend on top. Might need to make adjustments in the 2 inch also tecnicaly the 2 inch probely needs a clean out as well probebly on the horzontal coming out the wall. The santee on back never should have happened but I can see why my way eliminate

 

[Vinmassaro]

@Reach4, right, I'm planning to remove everything up to the last cast iron pipe and redo it, so that sanitary tee on its back goes away. Good point about the elevation, I will have to see what is possible.

As far as connecting to the existing CI, should I cut the hub off the last pipe and use a 3" CI to 2" PL no hub coupling or use a reducing donut inside the hub instead? Thanks!