Fernco Donut vs No Hub Transition Coupling? Plastic to CI drain

[JaCkaL829]

Hello all,

Hope everyone is staying safe and healthy. I have a powder room (toilet and sink) on my first floor that needs all the drain pipes replaced. Luckily the section of my basement isn't finished so the pipes are all exposed. It's the older XH cast iron, and has quite a few large cracks in it. I plan on replacing it all with 4" PVC. I have a cast iron main stack that is in OK shape, and if I can avoid touching it, I would be happy, don't won't to open pandora's box.

I attached 4 photos, the drain for the toilet and sink have a horizontal run, then hit into a 45 degree bend, run at an angle, then tie into the main vertical stack drain. I obviously need to cut the pipe somewhere to tie into the pvc. I'm wondering what would be the 'preferred' or better way of doing it? Should I cut the pipe straight and just put a no hub transition coupling (red line), or are those fernco donuts preferred? I was thinking of cleaning out the bell of the cleanout to keep it (inserting donut where it's orange). I know my father has done this before, he said he just made a bunch of drill holes in the lead, then used the sawzall. I also read you can heat it up the lead and it comes out easy. I'm a little uneasy with this process as I've read some people complain about the fernco donuts not fitting right as there are many different cast iron manufacturers. It was also recommended that I go to a local supply house for this particular donut. I favor having the work done correctly, as opposed to the least amount of time to complete the job. I'm quite sure the no hub route would definitely be easier.

Any guidance would be greatly appreciated. My house is North Jersey and is probably around 100 years old.

 

[Mr tee]

I would cut it at the red line and using a shielded reducing band transition to 3". You don't need 4" and 3" is cheaper and easier to work with. If cutting the cast iron goes south you can fall back to a donut.

 

[Sponsor]

 

[Jeff H Young]

most likely I would do as mr tee suggested. I like to have 2 shots at this if some reason the pipe crushes or cracks then go to the hub . 1 or 2 or even 3 toilets is good on a 3 inch line.

 

[Mr tee]

If you are tying into a 4" vent and there is plenty of room and not much distance that would be a case for sticking with 4".

 

[JaCkaL829]

Thank you for the replies! I was leaning towards cutting and using the no hub shielded transition as well. I'm guessing it's OK to use one on a downward slope pipe like that? I also agree about it giving me more 'options' should it go south and the pipe crack or fall apart. I've been on the fence about to use 3" or 4". It's already piped with 4" so technically speaking there is space, as I'd follow the same existing drain line, but I agree that it's probably cheaper and easier to work with 3". There is a 2" vent right after my closet bend (in the powder room) that I had planned on reusing just tying in with pvc and no hub transition as well. This may sound naive, but I've never had a clog/issue with the current 4" drain, I'd hate to do all this work with 3" and have issues. I have read people saying 3" has a better 'flow carry', so I don't know, still up in the air with it as I plan this project out.

Thanks again!

 

[Jeff H Young]

Normaly I agree bigger is better but a well installed system dosent cause many problems plastic seems to flow good I almost never run 4 inch when 3 inch is legal. but when fall is an issue my code allows less fall on 4 inch than 3. Very few modern houses run 4 inch through out a house that has 3 or fewer toilets. whichever size you choose will be fine

 

[Reach4]

If you go with 4 inch PVC, you probably need Fernco 3000-44 or P3000-44 or Mission CP-44.
https://www.fernco.com/sites/default/files/dimensional-drawings/pdf/3000-44.pdf

If you go with 3 inch PVC, you probably need Fernco 3000-43 or P3000-43 or Mission CP-43.
https://www.fernco.com/sites/default/files/dimensional-drawings/pdf/3000-43.pdf

 

[Jeff H Young]

cp 43

 

[Jadnashua]

Note, the XH stuff's OD may require a special banded coupler, and it would also require a different donut versus the normal duty CI, should you need to go that route. Fernco makes those in lots of sizes, since only the ID of the pipe is standard, the hubs are not (close, but no cigar some of the time!).

So measure carefully to ensure you get what you need before tearing things apart.

 

[JaCkaL829]

I understand about the 3" pipe being fine if you calculate the DFUs, as well as knowing people who have 3 baths on an entire 3" drain to the street. I have two connections that concern me with the 3", the first is the horizontal to 45 degree fall as you can see in the pic. I also have to make a 1/4 bend turn. I will be making that with a sweep, but have to use a street 22.5 into the sweep to drop the drain pipe for clearance of the joists. I'm no plumber, but it seems to me if my current setup is OK (Minus the cracks) not to mess with the sizing and path of the drain.

As for the no-hub coupling, there's quite a few options within Fernco for different matierals (Pvc, ci, copper, etc.) I was under the assumption I had to use a 'transition' band as I was going from two different materials (CI XH to Plastic). There is a band below that has that distinct specification.

https://www.fernco.com/dimensional-drawings/3005-44
or
https://missionrubber.com/product/band-seal-specialty-couplings-p-series-part-0804435/

I guess I would use the linked ones from Reach4 if I had just regular cast iron drain pipe?

I also have to note, I didn't realize there was a difference between schedule 40 vs drain pvc. It appears to me schedule 40 is slightly smaller, than the street drain. I noticed this when pricing out the pipe from Home Depot just to get a rough estimate, and the schedule 40 is more expensive. I understand schedule 40 can handle pressure as opposed to drain, but so many pvc drains I've seen are schedule 40. I'm wondering if it's just more convenient to get, or is there something more to it? My plumber re-did my entire kitchen sink drain with it.

 

[Reach4]

I also have to note, I didn't realize there was a difference between schedule 40 vs drain pvc. It appears to me schedule 40 is slightly smaller, than the street drain.

Some drain (DWV -- drain, waste, vent) is the same size. Some drain stuff (the green stuff in 4 inch or thin stuff) is not the same size. I would not use that for your job. Go schedule 4o, and not SDR 35 and not solvent weld D2729 sewer pipe.

Some schedule 40 size pvc pipe is solid pvc, and is pressure-rated. Still good for drains (DWV -- drain, waste, vent), and is stronger.

Foamcore schedule 40 is lighter and is DWV only -- not rated for pressures more than what you might test a drain system with. Different people have different preferences between those when doing drain work.

The fittings made for pressure can be used with either.

 

[DIYorBust]

The the no-hub coupling would be my 1st choice. There's time where a no hubs won't work, like say you must tie in at a wye for example. But getting the donut to seal in a hub is much more likely to be a problem than the no-hub joint.

 

[Jadnashua]

With a donut...you can't just assume, you must measure and ensure you have the right size. They come in numerous incremental sizes to fit securely into the hub...too small, it will leak, too tight, you probably won't get the pipe inserted in the middle...just like Goldilocks, it has to be just right to work. Not hard, IF you measure! Hassle is,you may need to order it.

I think you'll find that the XH OD is larger than the standard one, so your nohub will have to be sized properly, too.

 

[DIYorBust]

Yes but you have to unlead the joint, vs just cutting out a section.

 

[JaCkaL829]

I think you'll find that the XH OD is larger than the standard one, so your nohub will have to be sized properly, too.

I’m concerned about that as well. I though the no hub transition couplings that go 4” ci xh, pvc etc. would be adequate. I do think I’ll go to a supply house to pick one up as I’m sure they should have what I need.

 

[Reach4]

Have you measured the OD of the pipe you intend to cut? A long reach digital caliper is the tool of choice, but measuring the circumference and dividing by pi works too.

 

[JaCkaL829]

Just an update, I’ve been buying a bunch of different small tools, and extra fittings to have on hand when I start. Yesterday, I successfully cut all the old cast iron out with my fathers help. The cast was in incredibly poor shape, and what a relief it’s out. Big take away was the Porter Cable sawzall and the Diablo Heavy Metal blades worked incredibly well at cutting 4” XH cast. Each cut required a good amount of planning, and reinforcing with 2x4 braces and ratchet straps. We did cut cleanly to where I will tie pvc into the main stack, it’s capped for now.

I also made the decision to use 3” instead of 4” after your feedback, along with looking at a few friends newer construction of additional bathrooms.

So next step is planning out the new path of the toilet drain and sink drain. I did open up all the wall to correct the plumbing vent, and to insulate. I plan on redoing the sink drain and going up 42” to tie into the 2” drain. Whoever did this last did a crazy, and probably illegal vent.

Thank you all for the help, hope the rest is smooth as well.

 

[Reach4]

The cast was in incredibly poor shape, and what a relief it’s out.

You did not exaggerate. I wonder why your CI rotted away.

 

[JaCkaL829]

You did not exaggerate. I wonder why your CI rotted away.

I'm not sure why either, maybe the pipes weren't pitched correctly, or the poor job of the more recent tie in with pvc? Either way it doesn't matter it had to be removed, and luckily the main stack appears to be in good shape, with no signs or smells of damage.

 

[Jeff H Young]

not unusual to have bad sections and some that are solid Horizontal lines got wet sludge in them just laying there wet and the vertical is clean and lasts longer . Your headed along well re plumb that lousy vent like you said should turn out great!