Repiping - Flange too high

I'm repiping a lead drain with PVC. I have a 4" CI wye, with a brass ferrule extending from the hub. From there, I have a 4" mission coupling, a short piece of 4" PVC, a street 1/16 bend and a standard 1/16 bend, a 1/4 street bend, and then the flange. The flange fits inside a 1 3/4" tall piece of pipe, which fits inside the 1/4 bend's hub. The two 1/16 bends are included to shift the flange to the right two inches.

My problem is the bottom of the flange will sit a full inch above the finished floor.

I assume it is not proper to shorten the length of the hub on the top of the 1/4 bend? If the hub was shortened by ~ 1", that would leave 3/4" for the connection to be made with the flange's spigot.

What about turning the 1/4 bend around so that the street end pointed up, and cutting this end off ~ 1"?

If trimming the fitting shorter is a bad idea, is there another fitting I could use in place of the 1/4 bend that is 'shorter'?

I have this problem because floor joists in this room are only 2x6's, which leaves very little vertical room. The old lead drain didn't have this problem, as it drooped down a bit. I assume this would have allowed a bit of water to sit in the drain at all times -- probably not a good thing (??)

Thanks in advance for the help.

Zach

Okay, this is what I'm going to do to make this work.. Someone jump in and steer me straight if there is a problem with this setup:



What I don't like is that it goes from 4" down to 3" at the bushing, and then back to 4" for the remainder of the drain. I guess there's no problem with this though?

The closet flange is shorter than the 4" 1/4 bend, so my flange should be a bit lower.

In my unprofessional opinion, I believe there is a problem with reducing 4" to 3" then going back to 4". You are creating a constriction that will cause problems. I would advise not to proceed until you get some professional advice.

Zach said:

I'm repiping a lead drain with PVC. I have a 4" CI wye, with a brass ferrule extending from the hub. From there, I have a 4" mission coupling, a short piece of 4" PVC...

Click to expand...

Quick question Zach. I'm facing a similar situation.

How did you get access to the brass ferrule? Is it still encased in lead wipe, or did you remove the lead layer? If so, how?

I can't find any mission couplings that will fit around the outer diameter of my brass ferrule (which is still covered in lead wipe) and I don't have a torch hot enough to remove the lead.

Thanks!
.../j

Doh!

Just saw your thread on this with detailed step-by-step pictures!

Did you use a propane torch? or something hotter?

Thanks!
.../j

I'm pretty sure you would never pass inspection...drains can step up as the go down, but never the other way. My unprofessional opinion. With that restriction, you'd never be able to properly clean out the (probably inevitable) clog.

jch said:

How did you get access to the brass ferrule? Is it still encased in lead wipe, or did you remove the lead layer? If so, how?
...
I can't find any mission couplings that will fit around the outer diameter of my brass ferrule (which is still covered in lead wipe) and I don't have a torch hot enough to remove the lead.

Click to expand...

You will have to remove all of the lead from the brass ferrule. At it's thickest point, there was probably 1/2" of lead all around the ferrule. I melted off at least a couple pounds from my closet drain.

I just used propane, which is all I have experience with. I had plenty of heat. MAPP might have worked better (i.e. quicker), but just keeping the inner blue flame of the propane about 1" long, I was able to melt off the lead fairly quickly.

What if instead of a 3" to 4" closet bend, I used a 3" 1/4 bend? Then I would have 3" pipe from the flange all the way to the flush fit bushing.

The flush fit bushing does bother me a bit, the more I look at it. It seems things could get 'trapped' just past the bushing on the 4" side of the pipe. But, I don't have room to use a tapered 3" to 4" adapter.

It is ok to transition from 3" to 4" in a horizontal span, right?

Yes, you can increase size going away from fixture, downstream in other words, but not decrease. This is the way home drains work. 1-1/2 or 2" empties into a 3" or 4", a 3" into a 4", but you never go from a large to a small, even briefly. Always increase going away.

Below is my revised plan. I will start at 3" at the flange, and then increase to 4" after the first 90* bend.



I'm assuming it's fine to use 3" for a closet drain. Below is a drawing of my vent setup. (The lav and wc are the only fixtures on this stack).



Again, if anyone sees any problems with this setup, let me know.

Thanks again for the help.

-Zach

Going back to your original question on flange height, I would reduce the length of 3" pipe in your last sketch. Do you have the entire floor opened up, and can you add 3/4" of height to deal with the issue of short 2x6 joists? I would get the plumbing correct, and re-do the flooring if you can.

chassis said:

Going back to your original question on flange height, I would reduce the length of 3" pipe in your last sketch. Do you have the entire floor opened up, and can you add 3/4" of height to deal with the issue of short 2x6 joists? I would get the plumbing correct, and re-do the flooring if you can.

Click to expand...

If I use a 3" 1/4 bend, I will have no height problems. I can use the correct length 3" pipe from the top of the 1/4 bend to the flange.

I do have a problem if I use 4" the entire way, as the height of a 4" 1/4 is greater than the height of a 3" 1/4 bend. The upper hub of the 4" bend even lies above the finished floor.

As for the floor, I have complete access. I've pulled the whole subfloor, as it was rotten from a previous owner's "repair."

I think I have the problem solved -- assuming everything in my most recent sketch looks ok.