Need Guidance On Replacing / Updating Copper DWV Lines

[cz32]

I have started renovations on a master bathroom and have been contemplating fixing / replacing the drains for this bathroom. Bathroom has been gutted to studs and subfloor. House is from the late 50's or 60's. Located in Maryland. Here's my reasons for looking into this:

- Shower drain is not high enough for new shower base (will be traditional mortar, liner, mortar, tile shower pan)
- Would like to move shower drain a few inches to center it in new shower (old shower stall was smaller, new design puts drain close to one end)
- Toilet flange is beat up from floor demo (my mistake) and soldered to 3" copper pipe. May need height adjustment for new floor so replacement is ideal.


My concern is the layout of the existing drain system. It is not a continuous vertical stack. From the roof near center of house, vent pipe comes down in wall with kitchen on one side and guest bath on the other. Kitchen sink and guest bath sink connect to this pipe in the wall.

Once the pipe enters the basement, it makes a horizontal turn and heads towards the side of the house, perpendicular to the floor. The toilet for guest bath is attached with a wye just after the horizontal turn.

Next is a left turn towards main drain pipe. Along the way, the master bath shower drain, guest bath tub drain, master bath toilet and master bath sink all connect with straight, vertical tee connections. I suspect this was done because the guest bath and master bath share an interior wall and running everything inline was easier / cheaper? Is this even up to code anymore?

From there, the line makes a right turn, heads back to the foundation and into a main drain pipe. All of this is copper and brass with what I assume is a cast iron drain pipe.

No idea what to do, no idea if the existing configuration is up to code or allowed. I was thinking of just cutting the copper off for the master bath drains (branches), then replace with PVC.

Then I thought why not cut all the copper out between the main drain and guest toilet and replace with PVC as a preventative measure; but that would leave the vertical pipe and (newly finished) kitchen and guest bath with copper drain pipe. Is that ok?

We will likely be here for at least a few years so my dilemma is do I redo as much as I can now and consider it preventative maintenance? Or do I just do what I need to get the bathroom finished and functional / safe and just assume drain system may need more work or to be redone when it comes time for sale / inspection?

Any guidance would be appreciated!

 

[Mr_David]

DWV copper can rot out but it can also last for along time with no trouble.
All that looks to be accessible and looks to be in good shape So replace it when it fails. The stuff that might be up in the walls I would replace while you have it open.

 

[cz32]

DWV copper can rot out but it can also last for along time with no trouble.
All that looks to be accessible and looks to be in good shape So replace it when it fails. The stuff that might be up in the walls I would replace while you have it open.

Thanks! Any idea whether that configuration is "normal" or not? I always thought the drains were supposed to branch off of a main verical stack, not be inline on a horizontal run due to venting issues?

 

[johnjh2o]

Both the tub and shower are not vented. Horizontal to horizontal is OK if a Y and 45 is used.

 

[cz32]

Both the tub and shower are not vented. Horizontal to horizontal is OK if a Y and 45 is used.

So if I understand correctly, that would mean cutting out those tees and replacing with wye and 45 elbows -> to drains?

Would something like this be advisable or work at all? (rather than cutting tees out of main line). Can you run a vent up into a wall cavity with an access panel?

If not, what about running a vertical PVC pipe from horizontal run of shower drain, up through wall into attic and join into the vent stack?

Just trying to figure out if any of my ideas are feasible, and worth it or if I'm better off just replacing just the shower drain line just for the sake of being able to re-position it and make a good fit with new plastic drain parts.

Also, after checking the toilet flange again, it's actually not damaged, just some old wax that made it look like the flange was bent. Should be good to use again so no need to replace.

 

[frodo]

2'' pvc/ 2'' trap, with a 2x1.5 bushing in the inlet side

 

[cz32]

2'' pvc/ 2'' trap, with a 2x1.5 bushing in the inlet side

And then up through wall / AAV?

*Edit - I mean, can the 1.5" go up about 50" or so and then stop in wall with AAV or does the whole thing go up and join vent in attic?

 

[frodo]

it actually depends on where you live and what code you are under

if it could go to the attic and tie into another vent, that is the best scenario

or, tie into another vent in the bathroom wall...that is possible as long as the tie in is 6'' above the sink

normally that is around 42''

the AAV needs to be at 42'' or higher with a access door.. >>IF<< it is allowed by your local code

 

[frodo]

...................

 

[cz32]

it actually depends on where you live and what code you are under

if it could go to the attic and tie into another vent, that is the best scenario

or, tie into another vent in the bathroom wall...that is possible as long as the tie in is 6'' above the sink

normally that is around 42''

the AAV needs to be at 42'' or higher with a access door.. >>IF<< it is allowed by your local code

Got it. Will have to review codes then. Thanks again.