I have a bathtub that has horrible drainage and its because of an old galvanized horizontal pipe that connects to the stack.

I cannot replace this pipe with PVC with a better slope without compromising the floor joist structure in the ceiling. Home is from early 1900s.

However, I do have the ability to run a new drain all the way down to the basement and add a y connector that would keep the old galvanized pipe as mostly a vent.

I am a little concerned with the space I have in the ceiling to pull this off but I think I can do it. I am more concerned about the small 2 in drop where the pipe exits to the stack if I use it as a vent. (Please see images below)

Can someone give me an opinion of what I have proposed? Would the existing horizontal pipe work as a vent in this situation or would I be making any regressions here?

Today: Today

Proposed: Proposed

Photo: Photo

  • are there any other things feeding the stack above where the existing drain connects? (and what are they?) – Jasen Jan 29 at 2:54
  • The toilet and bathroom sink drain into the stack at around the same height as the tub drain. – Sealer_05 Jan 29 at 3:27
  • your new setup may need to meet the building code and I don't have the skill to answer that, – Jasen Jan 30 at 5:13
  • I'd think you could just cut out the galvanized pipe and replace it with PVC. Why don't you want to do that? – Greg Nickoloff Jan 31 at 20:02
  • Because there is no room to piece one in between the joists because it would add knuckles and it's already extremely tight. – Sealer_05 Feb 1 at 21:02

It appears your floor joists are already compromised by being notched out for the old drain pipe. But, to answer your question, since you have no vent now I think your plan is at least an upgrade.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.