Cast iron pipe has rotted - best way to fix?

[Walkman]

I found a leak in my crawlspace from a waste line cast iron pipe under my kitchen sink. The slope on the pipe was wrong and I think water and debris sat in the pipe since 1966 and it rotted through.

The leak is coming from the end of the line with the pipe going through the floor. The Y with the pipe going off the right side went to a waste line for a W&D connection that is no longer used.

1) How much of the pipe should I replace with PVC?

2) Any idea what the trap that is capped off was for? Was is supposed to be a vent? Or perhaps something for the dishwasher at one time?

 

[JohnjH2o1]

That second trap was for a dish washer. Back in the 60's they had gravity drains.

John

 

[Sponsor]

 

[Cacher_Chick]

1) How much of the pipe should I replace with PVC?

Cut out as much as you want to and is necessary to ensure the plumbing will work for another 50 years. If you are sensitive to noise, consider using new cast iron instead of PVC.

 

[Walkman]

Thanks, I'll get rid of the capped trap.

Are there special rubber connectors I'm supposed to use to join the cast iron to PVC? I've only used the Fernco type for joining PVC before? I take it I have hubbed cast iron pipe. I should try to join at a straight section of pipe, right?

 

[Cacher_Chick]

You can install PVC into a C.I. hub using a rubber "donut" or you can use a shielded coupler if connecting straight PVC to straight C.I. You will need to determine the type of C.I. you have, it may be standard or XH, (extra heavy) which is also common.

Fernco is a name brand. They manufacture all kinds of rubber donuts and couplers for putting pipe together.

 

[Gary Swart]

Most DIY refer to the neoprene sleeve with 2 hose clamps as a "Fernco". Well, Fernco does make those, but that type is for underground use only. For above ground use, you need a banded coupler or no hub connector. These have a clamp that covers the entire sleeve so they will support the connection. These are also made by Fernco as well as other brands.

 

[Walkman]

OK - so on the left side of picture above, should I cut the CI pipe right next to the hub (with the metal support strap) and then use a sleeve that will go over the hub? Or should I just cut in a straight part of the CI pipe?

 

[Cacher_Chick]

I would remove the section of CI pipe from the hub and install new CI or PVC into the hub using a donut.

There is no such thing as a sleeve which goes over a hub.