When do you need to replace a cast iron P-Trap? Take a look. This is a tough one...

[SomeOldGuy]

So. We're getting closer.

As you can see we have copper going into a cast iron P-Trap. My original plan was to remove the trap and cut back to the CI pipe, Fernco it, and then replace with ABS (or PVC? or...?).

The issue is that the P-Trap quickly makes the way under an adjacent bedroom (finished floor) - and based on the angle, I may not be able to dig back enough.

There does not appear to be any signs of leakage, the pipe is most definitely pitted (it's from 1965/66) but it doesn't crumble etc.

I'm torn here.

If I leave it, I assume the proper choice would be to cut the vertical copper (use Fernco?) and move the tub drain assembly (shoe and over/flow) tot he location where it needs to go for the new tub.

This is the shoe (not actually bought from HD LOL):
https://www.homedepot.com/p/America...rain-in-Brushed-Nickel-1640-305-295/202517975

Keep digging? or?... Thoughts.

Here are the pics...

 

[WorthFlorida]

I'm no plumber but it's a hard call to make. To cut out just the trap it'll take more digging and to get a cutting tool to it looks like it will be a tough job. CI average about 80-100 years of use and were built to last 50 years. If you cut it out do use a Fernco Coupler with a stainless steel collar. The new tub drain may not be in the same place as the old tub and to make a new connection to the old p trap may cause more issues fitting in the new drain. If you pull out the copper from the trap you'll need a Hub Donut to make it work. Not sure what size trap you have.
https://www.homedepot.com/p/Fernco-...h-40-PVC-Compression-Donut-P22U-205/100372278

If the old trap ever fails you will not know it and getting access to it in the future will be a big problem. The horizontal pipe might fail before the trap does. If you can get a camera to see the condition from the inside it give you a better idea on the course of action. At the circle looks like a crack is developing. Dig below the trap and feel the pipe if the CI is giving away.

 

[Sponsor]

 

[Sylvan]

One of my accounts has a mansion built in 1865 still has the original CI

My house was built in 1921 still original CI underground and in the main floor walls


https://en.wikipedia.org/wiki/Riverdale,_Bronx

 

[SomeOldGuy]

I looked more carefully at the area in the yellow. It appears it was some dirt that was sorta still "packed" under there.

This particular house is located in coastal SE Florida (on canal) -- so the longevity of CI is not as great (many homes have to be replumbed from below)...

Which... let's face it -- if this CI is bad, likely more of it is - and a whole replumb (or lining) is going to be in the future.

I think the prudent thing to do is to leave it. I believe that the trap goes into a wye (or similar) because the closet flange is very near. So I won't get my goal of replacing unless I make the job much bigger (replace closet flange, etc. -- which... BTW... was already done... which is why I have the concern about replacing this trap (hope that makes sense)).

Onward...

I'm assuming trying to remove that copper from the could result in another set of problems... so my plan was to Fernco from that copper vertical pipe to bring the shoe and drain to where it needs to be.

Or is removal and donut better? I'm concerned about wrenching that copper out of that CI.

 

[Reach4]

Note that for some things you do, you may be better to connect a new pipe to the yard, and join the drainage outside -- even if it means routing around the house. That would be to avoid cutting up slabs.

 

[SomeOldGuy]

Agreed. We're going to leave that trap. I'm just trying to determine what is best. To come off the copper stub at the top of the trap or to try and pull from the hub at the top of the trap.