Replace an Irregular-Sized Cast Iron Pipe with PVC

[dgal0215]

I'm looking to replace several feet of damaged cast iron pipe in my house (built in 1900). My plan was to cut out the cast iron section and replace it with PVC pipe, which would be coupled with the old piping using a coupling band.

The problem is that the diameter of cast iron pipe is 2 1/2 inches, which seems to be irregular nowadays as the closest pipe / coupling band diameter I can find is either 2 inches or 3 inches. Does anyone have any recommendations on what to do, or where I can find 2 1/2 piping / coupling bands?

[Eigenvector]

Is the pipe normally under pressure? If not perhaps there is a flexible sleeve that can be used, I've seen them advertised.

[dgal0215]

The pipe is part of the DWV stack (only a few feet below the roof) - so my guess is that it is not under pressure.

[John Keiser]

Check out the various products at

[Meat Plow]

Flex would work just fine for that vent.