Watch the video here, starting around 19:30
http://www.thisoldhouse.com/toh/tv/v...782908,00.html
There is no straight pipe exposed to attach a Fernco to. In addition
(no pun intended) it's a rubble stone foundation. I doubt you could
easily chisel the rock out to expose enough pipe for a Fernco.

It's hard to tell from the video, but it still looks like there's a little
bit of pipe between the hub and wall. I didn't realize it was a stone
foundation, but that probably means there's just mortar around the pipe
which would be a lot easier to chisel out than concrete.

I don't know if Fernco makes a donut that is not also a reducer.

I don't know either, I have never needed to use one. All of the work I have
done these days uses three inch PVC anyway, which slips inside 4" cast iron
easily.

Anthony Watson
www.watsondiy.com
www.mountainsoftware.com