Old cast iron shower drain needing a new pvc drain for tile.

[shooteneq1]

I have a shower remodel I am doing and have a plumbing question. I am redoing the walk in shower and have the floor dug up and removed and need to remove the old drain and connect a new PVC drain for tile. I think this is a cast iron pipe. How do I go about correctly installing a PVC pipe to the old drain? I have been trying to remove the current drain with no luck and might end up needing to cut the thing off. If I have to do that what is the correct way to connect the new pvc system to it. I want it to be done as right as it can be with no potential for leaks as I am in Florida and don't want the potential for small amounts of water leaking under the slab due to the amount of subterranean termites we have down here. I asked a guy in the plumbing department at Lowes and he said to sink a new pvc pipe as far as I can into the old drain but that just seems wrong on so many levels as that would not create a waterproof seal where they come together. He said you then use plumbers putty around the pipe where it meets but this just seems like a hack way to do it, but maybe its not that's why I wanted to get some professional advice on how to do it right.

 

[TomFOhio]

The way he told you is not the correct way to do this. If its cast iron you'll need a bigger hole to cut this with a
sazall and cast iron blades. You could rent a chain type snapping tool or use a wheel cut off tool. Cut it down about
an 1 1/2" above the p trap and install a mission coupling and then pvc pipe and your drain. Tighten it up and your in
business. If its 2" that's the size of coupling that you'll need.

 

[shooteneq1]

The way he told you is not the correct way to do this. If its cast iron you'll need a bigger hole to cut this with a
sazall and cast iron blades. You could rent a chain type snapping tool or use a wheel cut off tool. Cut it down about
an 1 1/2" above the p trap and install a mission coupling and then pvc pipe and your drain. Tighten it up and your in
business. If its 2" that's the size of coupling that you'll need.

Thanks. I am not plumbing pro but his advice just sounded absurd. I thought using a coupling might be the way to go but do these actually stay together over the years repacked with dirt and concrete over top of them? Also I am a solid 15" down and still have not found the p-trap or an elbow on this damn thing, are the typically much further down that this, and if its just an elbow should I dig this slab out further and go ahead and add a p-trap while its open?

 

[TomFOhio]

If there is a p-trap then just cut the pipe as low as needed to get your drain in. If there isn't one there should be one. If you can
find where the pipe turns horizonally it might be easier to cut and then put a pvc trap in.

 

[shooteneq1]

If there is a p-trap then just cut the pipe as low as needed to get your drain in. If there isn't one there should be one. If you can
find where the pipe turns horizonally it might be easier to cut and then put a pvc trap in.

Thanks, I found the P-trap and it is there, it will be to much of a pain where everything is located and how deep it is to change it to a pvc p-trap. I cut the slab out enough to get my reciprocating saw in there to cut it off the pipe off 2" above it as suggested. Thanks for the info it helped and makes sense now that I got it all open and ready to go. I plan on cutting tomorrow morning and making my connections. I guess my last question would be how do I fill this giant hole back up lol. Do I literally just bury the new connection and hole in the dirt and tamp it all back down and then refill the slab portion with new concrete?

 

[frodo]

if you found the old cast p-trap it makes no damn sense to leave it in the ground except lazyness
SORRY, I do not mean to hurt your feelings, I am a plumber not a counselor or dear abby
If you need to make the hole bigger, do it.
after you have removed the old trap, replace it with a new trap, and use a
Pro-flex 3000-22 2" CI, PL, ST or XHCI to 2" CI, PL, or ST
or a mission band CP-200 equilivent
to attach your pvc to the CI.
after the trap is installed, put a piece of pvc in the trap,,,and leave it 6'' below the concrete
fill the hole with SAND, remove the dirt and stuff you dug out
place a coupling in the pipe, and set the drain BODY level with the concrete

 

[shooteneq1]

if you found the old cast p-trap it makes no damn sense to leave it in the ground except lazyness
SORRY, I do not mean to hurt your feelings, I am a plumber not a counselor or dear abby
If you need to make the hole bigger, do it.
after you have removed the old trap, replace it with a new trap, and use a
Pro-flex 3000-22 2" CI, PL, ST or XHCI to 2" CI, PL, or ST
or a mission band CP-200 equilivent
to attach your pvc to the CI.
after the trap is installed, put a piece of pvc in the trap,,,and leave it 6'' below the concrete
fill the hole with SAND, remove the dirt and stuff you dug out
place a coupling in the pipe, and set the drain BODY level with the concrete

Thanks. I am right there so even if its a bit of a pain if its the right thing to do i will remove it. I think this is the part you are refering to connect the new PVC p-trap to the old pipe correct?

 

[frodo]

that is the part. go back and forth from nut to nut as you tighten it to stop the band from scruntching up

after you install it.

pack the dirt in around the trap so it will not move
by pack, i mean use a 2x4 or something to pack it. do not leave it loose

if you use sand. it packs itself if you get it wet. wonderful stuff for back filling a hole

 

[shooteneq1]

Thanks for your help. I can tell you anything you want to know about tile, but plumbing I know just enough to get myself in trouble. I would rather defer to the experts so I can do it right the first time. Especially since doing it wrong means ripping all the tile work out.