Adding a wye to a 4" hub & spigot stack

tlowc34

My house is 92 years old with a kitchen reno done in the early 80s. All of the DWV are cast iron hub & spigot, except for the 80s reno. When they did the update, they moved the kitchen sink and dropped a 1-1/2" PVC drain down from the kitchen sink/garbage disposal. It currently blocks the operation of the basement window. Garbage disposal failed and wife hates the double sink so I ordered up a new single drain deeper sink and wanted to improve the way the plumbing is run to restore window functionality and improve drainage/prevent siphoning when going to a single sink by adding an AAV. The plumbing is all run to the right, but there is a whole mess of steam heat plumbing there. Would seem to make sense to move to the vertical stack on the left that is in good shape. I think I could cut it and add a 4x2 no hub wye and run it that way. Attached a pic of my previous repair as proof of ability to work with no-hub. Thoughts?

pecmsg

The only concern is that cast iron stack. Get it supported properly before cutting!

Also where's the Vent going up?

JUGHNE

Is there a reason the 2" iron riser could not be reused?
You could come away from the basement wall with your pipe up between the floor joists and then over to the extended 2".

That would get you pretty good clearance for the window to swing up.

Yes, that 4" CI stack can get pretty heavy and tend to slide down, maybe cracking any tee that might be hidden.

tlowc34

Didn't think of the cracking concern, but knew about the weight. Stack goes to the roof through a 2nd story bath. I was thinking I could use a riser strap and support it either temporarily with 2x4's under the strap or permanently at the floor joist area:

Here's a better view of what I'm working with around the existing 2" riser:


Maybe I'm just being too OCD, but I hate the inefficient clumsy routing. I don't know if there is a word for that in the trades. Crazy routes that use multiple bends, joints, bushings, etc. Like Don't take a 4" wye and then put a bushing on it, use a 4x2 wye that doesn't need a bushing.

tlowc34

@pecmsg it doesn't currently have a vent. I was going to use the air admittance valve, since I can't sneak a loop up over the water level of the sink. Thoughts?

pecmsg

I ran a 1 1/4” vent horizontal until I could go up. 

mattmia2

You certainly can cut in to the CI, but it will be a whole lot easier to re-route that current pipe with PVC even if you have to come over the steam pipes in the joist bay then back around. It probably once had a vent in the basement that was removed during the renovation. Think long sweep fittings and 45s in the drain section as much as possible. Street ells might get you in to some of the tight corners too.

If you actually want to come across to the CI stack by drilling the joists you will have to use several sections and couplers to get it in place which in itself will be a little ugly.

Danny Scully

@tlowc34, Cut the 2” gal below the window, then come up between the 2 windows.

hot_rod

I guess it depends on how much better you want it to look? I agree with a riser clamp and some all thread to the joist above for support.
Those new carbide sawzall blades are amazing and would zip thru that cast like butter, almost There have been a few demos of those new blades on IG recently. A few no hub bands and away you go.
I'd be reluctant to put a snap cutter on old cast, I have had it crush before it snaps.

tlowc34

@hot_rod I had trouble with the carbide stuff on the no-hub - I think the coating gummed up the blade. Might work better on the uncoated old stuff. I always just break out the cutting wheel on an angle grinder and finesse it to a marked line.

tlowc34

I might just go the really OCD route and fix the lazy rerouting of the steam lines near the 2" riser. The radiator in the kitchen has been moved twice and they just patched in more and more elbows and unions that are complicating the issue.

Jamie Hall

I don't usually slightly divert a thread, but in this case maybe someone can help... I have a situation where I need to connect new waste drainage (probably ABS, 3 inch) to an old cast iron 4 inch hub... in which there is a 4 inch stub about 2 inches long sticking out of lead (yeah, really) DWV. Which was beautifully wiped into the hub (those old guys -- around 1910) -- really did a truly beautiful job).

Suggestions? I'm thinking Fernco on the lead stub and new DWV...

tlowc34

Wouldn’t it make sense to go 4” lead > fernco > 4” pvc > 4”-3” reducing pvc coupling > 3” pvc/abs 
that way any lengthwise force doesn’t collapse the 3” -4” reducing rubber coupling?

tlowc34

There is the type that has a metal shield, but it looks spendy and there still isn't any lip for the end of the 3" pipe to rest against. It would all be friction grip on the OD to hold it in place.



https://www.ferguson.com/product/fernco-4-x-3-in-cast-iron-and-plastic-flexible-coupling-f105643rc/_/R-3083399

JUGHNE

IIWM, I would drill out the lead pour in the hub.
1/4" x 12" drill bit long makes it easy, hook out the lead and oakum with heavy wire (#9).
Then use a 4 x 3 Fernco donut to put the PVC directly into.

Give or sell the lead to an ammo reloader.

tlowc34

@JUGHNE I thought about this approach, but how do you stop the 3" from continuing to push into the 4" lead past the donut? Is there a positive stop on the donut? Or is it unnecessary?

I used the donut for 4" no-hub to 4" hub & spigot and the no-hub banks on the bottom edge of the hub.

Jamie Hall

Bravo! I knew you folks would have good ideas. Onwards... hadn't thought of using the lead for ammo reloading... with the state of ammo supplies these days, not a bad idea at all!

JUGHNE

I place a bury mark with a sharpie on the pipe to avoid that.
Usually have to taper the end of the pipe and wire lube both the donut, hub and pipe. Sometimes just install a short piece, some need a block of wood and sledge hammer on the short PVC.
Hub castings can vary a fair amount, seldom to big.

For one that was too loose for donut, there is a PVC hub adaptor.
Used oakum and then "Plastic Lead" for that one.

Jamie, my father plumbed his house in the early 40's.
Lead was in short supply, he used some form of cement where the lead pour would have been. Still holding today.
But if you flex the joint at all the cement cracks, found out moving a 1 1/2" drain and then went to the donut.

GW

I’ve done this a bunch, hit me if you need more ideas

dopey27177

The minimum drain size for a kitchen sink is 2"
The trap should be 2" and the drain size 2". Additionally, there should be a vent for the drain line of the sink.

Not all codes allow air release fittings below the flood rim of the sink.

In Florida the air release fitting can be installed under the sink.

Jake

EBEBRATT-Ed

1 1/2" is minimum for a kitchen sink around here.

Intplm.

The code in my neck of the woods changed from 11/2 to 2 inch some years ago. One of the reasons was to help for a better performing drain if a disposal was ever to be added.