PVC into cast iron hub

[mdzialo]

A second floor toilet developed a leak, so I decided to do the bathroom over. I've taken everything out and taken up the floor. The cast iron stack has a cast iron tee with a hub. A field formed lead closet bend was leaded into the tee and went right to the toilet. That lead closet bend developed a leak during the early '70 and was repaired using tar, cloth and string, I guess (thats what it looks like). That repair started leaking again.

Since I want to move the toilet about 7' down on the adjacent wall, I cut off the lead closet bend with a sawsall (very easy). Now what?

I'd like to use PVC going into the cast iron hub. I see a product called a Fernco gasket that is used to connect cast iron and PVC and that might work. My question is this: Do I really need to remove the remaining piece of lead pipe which was leaded into the cast iron hub and left in place when I cut off the lead close bend?

That remaining piece of lead pipe is perfectly clean and leaded connection is perfect, too. The inside opening measures 4 and 3/15" with a ruler. It's such a good job that I hate to ruin it.

But if I do need to remove all that, how? With a propane torch, on my side for hours trying to melt the lead connection? Tell me there's another way.

[LazyPup]

You will need to remove the lead, fortunately its a very easy task.

Grab you electric drill and a bit approximately 3/8". Drill a bunch of into the lead real close together. The idea is to try to break the lead ring with the holes. Once you have three or four holes drilled through the lead you will be able to insert a large screwdriver and pry the lead away from the hub wall and in toward the center of the pipe. As soon as the lead starts prying inwards it will all pry out real easy.

Next clean the old oakum from the bottom of the hub. It will look like bits of frayed hemp rope that will most likely be very black and gunky.

Once you have the lead and oakum pried out you can clean the inside of the hub with a wire brush and wipe dry with a rag, then you will be ready to begin making up your new joint.

Fernco makes a rubber donut gasket that will fit over your PVC and insert into the hub but I prefer to insert the PVC into the hub, then pack 1/2 the depth of the hub with new Oakum and cap it with Plumbers Epoxy in the same manner as the lead was originally poured in. (Plumbers Epoxy is a two part roll that has a grey and a white layer. You knead it together to activate it until the expoxy putty turns grey then its ready to pack in the hub. It will set in about 5 to 10 minutes after installing.

[mdzialo]

Thanks. That job doesn't sound too bad. I'll try the clean out tomorrow.

[mdzialo]

I cleaned the hub. Looks great but it took me several hours with some rests. I think I'll look at the good job for a couple of days before I move forward. By the by, the piece of metal leaded into the hub was brass.

[LazyPup]

Once you have the hub cleaned out installing the new pipe is easy.

On the downstream end of your new pipe you will be using the hub you cleaned out. "Fernco" makes a donut gasket that will fit around the OD ( Outside Diameter) of the new PVC or ABS and will fit the ID (Inside Diameter of the hub) to complete the joint.

I prefer to insert the new pipe into the hub, then tightly pack the space between the hub and the pipe will with Oakum until the hub is at least 1/2 full, then top it with Plumbers expoxy.

On the upstream end you will have the new PVC or ABS butting against the end of the existing cast iron pipe with no hub on this end. You simply install a Fernco CI x PVC (Cast iron x PVC) coupling or a "No Hub" mission band clamp. You must be sure to measure you new pipe carefully to minimize the gap between the existing pipe and the new pipe.

[mdzialo]

The hub that I cleaned out is part of a tee in the stack which goes up throught the attic and vents out the roof. I will insert a new PVC or ABS pipe into that hub and secure it using your oakum and plumbers epoxy method that you recommend.

There is no upstream pipe to connect into. I want to go from the stack to the new toilet that will be about 7' from the stack on the adjacent wall.

Which product is better to use, PVC or ABS for this soil pipe?

[LazyPup]

Both PVC and ABS will perform equally well, however you may have some local code restrictions on which material you may use.

When running your waste arm from the stack to the watercloset keep in mind that you must maintain a minimum of 1/4" per foot pitch, pitching downward from the closet flange to the stack to insure a good gravity flow.

When installing the closet flange, the underside of the flange should be flush with the finished floor, which leaves the top surface of the flange about 1/4" to 3/8" above the floor. (The code prohibits installing the flange with the top surface flush with or recessed below the finished floor.)

When installing plastic pipe (ABS, PVC or CPVC) you may not use metal wire, metal strapping or metal hangers to support the pipe. If you require supports for your waste arm you should use the PVC perforatated strapping or formed plastic J-hooks.