Question here on what those here think the best way is to hook up an addtional toilet to a cast iron drain….
Existing situation is this:
Second floor has a bathroom in it. It’s a small full bath. The toilet in this bathroom has a main cast iron stack that runs down to the basement. All typical, nothing special here.
The HO wants to take the adjacent small bedroom and turn it into a master bathroom, one that is much more spacious. The existing bathroom will become a general bathroom for household guests. The HO wants me to rip out the CI stack all the way to the basement and replace with PVC. I’m going to discourage the HO from doing this because A) the existing stack passes inside the wall between the DR and KT, B) PVC will be noisy and unappreciated when dining and the toilet is used and C) the CI is in excellent condition, nothing wrong with it.
However, the delimma is this. In the new master bath I can put the master bath toilet up against the same wall that the toilet is on in the existing bathroom, thus sharing the same drain stack and the two toilets would be back to back on the same wall. But, I’ve never done this before and am wondering how on earth would you attach a 3″ PVC tree fitting onto the top of CI and make it leakproof. By tree I mean two 3″ side inlets opposite each other to accommodate the two toilet drains with a central branch outlet going upward to attach the existing CI vent to that protrudes thru the roof today.
Do you somehow fernco it (which I doubt, I can’t imagine it being legal to conceal a fernco in a wall much less ANY fitting that uses a mechanical connection being legal to bury in a wall) or do I price the job using a CI tree fitting and somehow figure out how to attach it to the CI stack (can’t use lead since lead won’t flow uphill)? Even more scarier for me is that when I go to snap the CI with a CI cutter to remove the existing toilet branch drain, the CI will likely break unevenly, how do you deal with that in that instance? Or should I do as the HO wants, rip it all out and use PVC and save myself the aggravation?
Replies
I went through a similar dilemna with my own bathroom a few weeks ago. I had a lot of connections to make though, so i went with a total replacement.
If you want to keep everything cast iron, you'll have to take out the stack down to the next hub, or go with hubless fittings. no upsidedown hubs. I don't know where you could find them, but i do think that they make a tree that fits over CI and clamps down. seems like that should work, not sure about the legality of hiding it in a wall.
If you're worried about a messy cut, just use a grinder with a metal disc or a sawzall. leaves a nice cut, but slower than the snap cutter.
zak
Pretty involved. Thought of subbing that part out? Sounds like the wise thing to me and then in the future you will have already seen it done.
You can bury Fernco's in the wall. Legal and size wise it all works. Cut the cast using the grider method above or rent a cast iron pipe snapper. The big thing to remember is cast iron will support some of the weight (it is not supposed to but will) of the the toilet and tree assembly and plastic will not so everything needs to be properly braced and supported.
But it really goes together like any plumbing book at the library will show you, just fernco the assembly to the cast and vent. DanT