Cast iron or PVC or ABS under slab requirements

[Al S]

I have sought in vain to try and find what the requirements are for waste pipe under a slab (basement floor in my case). I have an original full bath in the basement. In planing the re-model, I am considering replacing the 1955 cast iron drain pipe under the floor that goes to the main stack. I have not been successful to find what the plumbing codes are for my town in Huntington Station, NY. I want to know can I replace the 2 inch cast iron with ABS, PVC or does it need to be cast iron again? As an added puzzling item, there does not seem to be a visible vent for the basement toilet. The main 6 inch (could be 8 inch too)main stack is only about two feet from the toilet. So I'm guessing it serves as a wet vent connected under the floor. Sometimes the toilet gurgles a little when flushing but it still works.

Thanks in advance,

Al

 

[John Gayewski]

NY is a tricky place. Why not call the nearest authority have jurisdiction. My educated guess is pvc will be legal.

 

[Sponsor]

 

[Al S]

NY is a mixed bag. NYC is hugely tight and wants cast-iron no matter what. My quest is for my township. Have you ever tried to get information from a municipal bureaucrat? They are the most difficult people to work with. They'll likely reply "...a homeowner has no business knowing this" and tell me to instead consult with a licensed plumber. Though I may do that anyway, I first want to know so at least I can determine which contractors know and those who don't.

 

[Reach4]

If putting in PVC under the slab, I would consider opting for solid PVC pipe ("dual rated") rather than foamcore DWV-only. It may be overkill, but it is what I would prefer.

 

[Al S]

If putting in PVC under the slab, I would opt for solid PVC ("dual rated") rather than foamcore DWV-only. It may be overkill, but it is what I would prefer.

By that do you mean schedule 40 PVC? What about ABS? In both cases it's easier to me than cast-iron. I just want to know if there are rules for this. I want to do it the right way but would prefer not to use cast-iron

 

[Reach4]

delete

 

[wwhitney]

Usually 1/16 inch per foot is enough slope.

For sizes 4" and under as you'd typically see in a residence, I'm not aware of any plumbing code that would allow only 1/16" per foot slope (0.5%).

As to the OP, my understanding is that outside of NYC, NY state uses the IPC. In which case you can use Schedule 40 ABS or PVC under your slab.

Cheers, Wayne

 

[Reach4]

For sizes 4" and under as you'd typically see in a residence, I'm not aware of any plumbing code that would allow only 1/16" per foot slope (0.5%).

Edited to 1/8.

 

[Al S]

Let's think about something else: "overhead sewers".

Thanks but that's completely out of context to the discussion. FWIW, My main drain line goes under basement floor to a septic tank/sand leach pit system

 

[wwhitney]

The main 6 inch (could be 8 inch too)main stack is only about two feet from the toilet.

BTW, is this a single family residential building? It would be very unusual to see anything larger than 4" in such a building.

Cheers, Wayne

 

[Al S]

BTW, is this a single family residential building? It would be very unusual to see anything larger than 4" in such a building.

Cheers, Wayne

Hi Wayne,
It's a 3 BR single family ranch with a full bath upstairs and a full bath (shower stall) in the basement. Main kitchen drain descends into floor and into main line which is about two feet under the basement floor. It is 4 3/8 diameter pipe. Though not in frame, the toilet in the basement is on the other side of that stud wall about 2 feet away

 

[wwhitney]

It is 4 3/8 diameter pipe

OK, that means it's nominal or trade size is 4". And even if it is old, its dimensions match modern no hub cast iron dimensions, which are 4" ID and 4-3/8" OD for trade size 4".

Cheers, Wayne