Bad advice??

I'm an avid DIYer, with a new project I'm planning out that I have been gathering information for. Part of said project involves transitioning from Cast Iron to PVC, 4" soil stack. The owner of the local hardware store, where I worked for a time years ago, and whose advice I usually trust, said a plain Fernco coupling (no shielding) would be fine, and is code-worthy. This seems to contradict what I've read in this forum and others and I was wondering if there are ANY unshielded couplings that would be approved for this purpose (vertical stack, cast iron from basement to PVC up to kitchen sink and second floor bathroom).

One follow-up about the shielded couplings: can the rubber part be rolled to allow the two pipes to be fit? I don't have any wiggle room to bend or move the pipes, and I can't see another way to attach a fitting.

One more follow-up: the cast iron is the hub type. I plan to cut the pipe to make the end a no-hub, and then use the fitting to go to Sched 40 PVC. Are there concerns that the pipe OD's won't be close enough? Are there some old CI pipes out there that might have odd OD's? How far from the PVC would be acceptable (1/4"? Less?)? Or do both pipes need exactly the same OD?

Thanks for any and all advice (but especially good advice),
Mike

Unshielded couplings are only approved for below ground where the pipe ends can be supported which keeps them aligned. Above ground, you are required to use the shielded version. Yes, you can fold it back on itself, but it is a little tight, it can be done (there is a ridge in the middle that prevents you from sliding it down, then sliding back). Rather than cutting the hub off, you can get a Fernco donut and insert the pvc through it in the hub, also an approved solution. CI hub sizes are not tightly regulated, so getting the proper donut OD is critical. CI generally is available in 'normal' and X or heavy duty. WIthin one area, the plumbing supply will often have the right donuts, but measuring first is important. Too loose, it will leak, too tight, and it might be impossible to insert the pvc into the middle. It also depends on how old it is. I know I had trouble finding one the right size (quickly, anyway) when I tried to do some remodeling on my mother's house built in 1954.

I thought leaving the hubs alone would be a good idea for that very reason (finding the right size donut). If I cut above a hub connection and go with a no-hub, would I have better luck finding the right fitting? For 4" I read that the Mission CP44 would work, and I assume that Fernco makes one that would fit similarly (ProFlex of the correct size). Does that seem like an easier solution?

Mission makes series of couplings for both regular cast iron, and XH. So a coupling will be available, as will a donut. Can't tell you which will be easier to find. All the fittings specify what each end fits...for example you may need a CI to sch. 40 plastic, or an XH to sch 40 plastic. Etc.

I just went through this last week, though in my case old bell & spigot cast iron to new no-hub.

I had two recommendations, a CP44 adapter, and a TWC44 adapter (the one I ended up with due simply to what was available).

Original thread with a pic of the end result here: https://terrylove.com/forums/showth...pecial-adapter&p=267148&highlight=#post267148