pvc to lead to cast iron tub drain

[Bob999]

assembly I I am installing a pvc bathtub p-trap on an old bathtub. Should I :

1 connect the new pvc trap to the lead pipe with a shielded fitting, or

2. tear out a bunch of plaster in the finished kitchen below, tear out the 8 feet of lead pipe back to the cast iron, run pvc and attach it to the cast iron with a donut

or something else?

Thanks! Bob

 

[Twowaxhack]

I would replace all of it with pvc. That might require furring the ceiling down to accommodate the pipe.

 

[JG plumbing]

Yeah connecting to the lead likley won't hold.

 

[JG plumbing]

Cut and start here if you can.

 

[Bob999]

Thanks for tha advice - I appreciate it. If I cut it there I'd have to replace the sink drain pipe too. Do you think it would be okay to just take out the one lead pipe to the tub and leave the other one to the sink alone? Or should I replace both drain lines with pvc?

 

[Twowaxhack]

The lead was bent on site to odd angles. Pvc often doesn’t fit in the same holes...or at those same bastard angles.

Replace it all.

Good luck.

 

[JG plumbing]

Plus you have to grip the lead. I wouldn't trust it to hold, especially above a ceiling.

 

[Twowaxhack]

When the pvc doesn’t fit the angles or the existing holes you can’t enlarge them because it weakens the joists......ceiling might sag.

That’s why I say it may be necessary to fur the ceiling down below to accommodate the pipe.

I’ve done many of these jobs in our historic district.

 

[Bob999]

Would you recommend I cut the tub drain pipe at this point and tie in the new pvc here, or should I cut the 4 inch cast iron here and replace the approx. 6 feet of lead drain pipe coming from the sink also. I don't see any problems with the sink drain. Thanks again for the advice. Bob

 

[JG plumbing]

Cut and start here if you can.
View attachment 29994

 

[JG plumbing]

Pretty sure I already said that.

 

[Bob999]

Yes sir you did. I just wanted to make sure that I understood what you were saying - that you were implying that I should also demo and replace the vanity drain line. I was kinda hoping I could leave that one alone but that's why I asked the question, to get advice from you experienced guys. And I'll follow it. Thanks again I really appreciate your help.
Bob

 

[GReynolds929]

Better to replace it all while mostly accessible than not and have to anyway later down the road after everything is finished

 

[Bob999]

As much as I wanted you guys to tell me that a fernco on a lead pipe is bulletproof I think deep down I knew that I was living in fantasy land. I'll take your collective advice and demo and replace it all. Thanks again fellas for your help.