I've torn out an old shower stall that is in off our master bedroom
because it was leaking badly and had ruined the 2x4s on the threshhold
and some of the surrounding studs. The original construction was tile
over plain drywall for the walls and a concrete/cement shower pan which I
used a sledgehammer on to break it up and haul it out. Under the pan was
just the subfloor. I want to use tile on the walls again and a
fiberglass/plastic shower pan over mortar and 3/4 plywood base over the
The original drain connected to a 2" copper pipe using a lead/oakum
joint. My question is as follows. I know that there are adapters (Fermco,
etc.) that will connect cast iron and PVC but I don't know if they would
work w/copper and PVC. The copper pipe is 2" ID and 2 1/8" OD. The only
adapters that are close are 2" OD. Am I going to have to use a copper
reducer and the adapter? Short of replacing the drain piping underneath
the subfloor, what would be the best method to use in this case (assuming
local codes allow it)?
Remove the nospam to email me
Fernco makes a No-Hub style coupling expressly for joining
2" Cu to PVC/iron pipe sizes. You won't find it at HD/Lowes;
check at a real plumbing supply house.
If there was a Cu trap under the shower, I would replace it with
a PVC trap and make the coupling further back.
Thanks for the reply. I've been to 4fermco.com (or whatever it is) and
I've looked through their products. I was leaning towards the no-hub
style - based on researching this a bit. What makes you say that the
coupling should be farther back and to replace the trap w/PVC? Is there
more likelihood of a leak closer to the drain because of flexing, etc.?
I suppose one man's convenience is another man's PITA :) I _could_ cut
out the subfloor and replace when I'm done, I guess, but for me, it would
be much more convenient to cut the pipes to length and use the adapter.
What about the 2 1/8 OD copper pipe? Would the adapter stretch that much
(I'm thinking not) or am I looking at rebuilding the whole works from
further down the chain?
Hmmmm Some misunderstanding here. The shower pan will have
a drain fitting which accepts 2" PVC. That's bigger OD than 2" Cu.
Search Fernco for the correct adapter 2"pipe to 2" Cu.
You extend the drain upward with PVC so it fits *inside* the
drain fitting in the pan. Then a "calking ring" gets driven down
from above (you're sitting in the pan) to complete the connection.
This way you just drop the pan down over the pipe extension.
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