Dealing with old CI and copper drains in a remodel

[HilltopRehab]

I've demo'd our original 1958 master bath, and before I start to build up I want to address the old plumbing.

It's a 3/4 bath with a very small footprint, leaving not many options for reconfiguring so I will be leaving the layout as-is, aside from moving the shower plumbing from a partition wall that formerly framed the shower stall - planning on enclosing with glass partition and door.

After pulling up some of the old 3/4" plank subfloor that was water damaged and questionably supported, I can see that the shower drain is only 1.5" copper pipe, granted that's eyeballing a tape measure on the OD. I'd like to increase the pipe diameter and do it the right way, either myself or by a pro, so that brings me here seeking advice.

The WC drain pipe is 4" and the flange is at a height that I think I can work with, but I'm wondering:

• Should the whole branch be re-worked to incorporate a bigger shower drain and replace all three drains with PVC - see photo, both the sink drain (1.25") and the shower drain tie in just downstream of the WC flange on their way to the main stack.
• Should I try to un-thread the shower drain and see if that's already a 2-inch opening, is the right thing to do here going to be to replace the copper drain with PVC anyway?
• Or, should I try to minimize the amount of work and stick with the existing WC flange, using an adapter to go from the 1.5" shower drain connection point to a new 2" PVC drain?

I've included a photo from above looking down at the coupler between the WC elbow and the sani-tee on the main stack, where the sink drain comes in from the left and the shower drain comes in from the right.

Thanks for any advice!

 

[Plumber69]

I've demo'd our original 1958 master bath, and before I start to build up I want to address the old plumbing.

It's a 3/4 bath with a very small footprint, leaving not many options for reconfiguring so I will be leaving the layout as-is, aside from moving the shower plumbing from a partition wall that formerly framed the shower stall - planning on enclosing with glass partition and door.

After pulling up some of the old 3/4" plank subfloor that was water damaged and questionably supported, I can see that the shower drain is only 1.5" copper pipe, granted that's eyeballing a tape measure on the OD. I'd like to increase the pipe diameter and do it the right way, either myself or by a pro, so that brings me here seeking advice.

The WC drain pipe is 4" and the flange is at a height that I think I can work with, but I'm wondering:

• Should the whole branch be re-worked to incorporate a bigger shower drain and replace all three drains with PVC - see photo, both the sink drain (1.25") and the shower drain tie in just downstream of the WC flange on their way to the main stack.
• Should I try to un-thread the shower drain and see if that's already a 2-inch opening, is the right thing to do here going to be to replace the copper drain with PVC anyway?
• Or, should I try to minimize the amount of work and stick with the existing WC flange, using an adapter to go from the 1.5" shower drain connection point to a new 2" PVC drain?

I've included a photo from above looking down at the coupler between the WC elbow and the sani-tee on the main stack, where the sink drain comes in from the left and the shower drain comes in from the right.

Thanks for any advice!View attachment 69107

That does not look like its going be easy

 

[Sponsor]

 

[wwhitney]

Looks like that middle floor joist in your picture is in need of a repair. I'd be inclined to demo out all the drains to the cast iron san-tee and start fresh, after or as I repair the joists.

With a floor plan showing the fixtures, the location of the cast iron san-tee, the joist size and which way they run, we could advise you on a proper wet venting layout. What do you have for vents now?

Cheers, Wayne

 

[HilltopRehab]

Looks like that middle floor joist in your picture is in need of a repair. I'd be inclined to demo out all the drains to the cast iron san-tee and start fresh, after or as I repair the joists.

With a floor plan showing the fixtures, the location of the cast iron san-tee, the joist size and which way they run, we could advise you on a proper wet venting layout. What do you have for vents now?

Another image added below for clarity, and a very basic layout of the room - HOWEVER I drew the basic layout before I pulled up the planks at the toilet. The section of floor framing at the toilet is blocked and framed between doubled joists to allow for the 4" drain pipe. What you're seeing above is one of the 2x3 members that was laid out around the WC flange. I agree, my plan needs to improve the support for the floor in that area.

The sink is the small circle at left on the 36" wall, and the shower drain is the small circle in the opposite corner.

Joists are 2x10, 16" on center apart from at the toilet.

The only current venting is the main stack right there behind the toilet.

 

[wwhitney]

I'm having a little trouble reconciling your drawing with the picture, but based on the drawing, the typical thing to do would be that the rightmost full length joist would be doubled (assuming that's not an outside wall parallel to it), and then the area around the toilet would get filled in with joists perpendicular to that double joist. But that's just a general comment, I may be misunderstanding your framing.

So the toilet flange needs to stay lined up with the stack? Do you have room between the cast iron san-tee and the toilet closet bend to fit in a 3x2 wye? If so, then the standard wet venting would be to provide a dry vent for the lav (which can rise and tie into a vent stack above), then run the lav drain through the joists towards the toilet but a bit closer to the bottom of the page, then pick up the shower drain with a wye, and then hit the 3x2 wye between the closet flange and the stack san-tee.

Cheers, Wayne

 

[Jeff H Young]

complete repipe waste, vent and water my opinion. I am a plumber and I assume you would want to have some assurance that this floor wont be getting ripped out again in the near future.
Costly I know but wouldnt trust this existing for 5 to 50 more years

 

[wwhitney]

based on the drawing, the typical thing to do

I should amend my comments. How you'd head off the one interfering joist to create a hole in the floor framing to run your toilet drain perpendicular to the common joists would depend on the details of where the supporting walls are below and where the joists are on both sides, which includes the joist to right in the next room.

But my point was that once you've headed off the one joist, you'd typically fill in the hole in the floor framing on the other side of the toilet drain with joists parallel to the header, not to the common joists.

Cheers, Wayne

 

[HilltopRehab]

I should amend my comments. How you'd head off the one interfering joist to create a hole in the floor framing to run your toilet drain perpendicular to the common joists would depend on the details of where the supporting walls are below and where the joists are on both sides, which includes the joist to right in the next room.

I follow- the supporting wall below is basically immediately adjacent to the stack, there’s a bit of overhang below the wall with the window (to the left of the toilet when facing it).

Just to add to the discussion in case it affects the approach to re-plumbing: the next room is the hall bath and its toilet is back-to-back with this toilet. The heading off around the toilet is actually wide enough to support two toilets. The hall bath WC drain flows into the stack immediately below the master WC drain.

 

[HilltopRehab]

complete repipe waste, vent and water my opinion. I am a plumber and I assume you would want to have some assurance that this floor wont be getting ripped out again in the near future.
Costly I know but wouldnt trust this existing for 5 to 50 more years

That’s why I came here- an attempt to prevent myself from cutting a corner. I agree with you, I will probably get professionals in here to propose solutions for waste and vent.

 

[wwhitney]

I follow- the supporting wall below is basically immediately adjacent to the stack, there’s a bit of overhang below the wall with the window (to the left of the toilet when facing it).

Just to add to the discussion in case it affects the approach to re-plumbing: the next room is the hall bath and its toilet is back-to-back with this toilet. The heading off around the toilet is actually wide enough to support two toilets.

So can you update your diagram to show the joists under the hall bath, how many joists the header is carrying, whether the trimmer joists are doubled, and the location of the bearing walls below at each end of the common joist span? I would think you can tell all of that from the opening in the floor system you currently have, with the exception of the details on the trimmer joist under the hall bath, so that may have to be left unspecified.

The hall bath WC drain flows into the stack immediately below the master WC drain.

Do you know if the hall bath WC is separately vented or wet vented by the hall bath lav or tub/shower? Because if it is relying on the stack for venting, then both WCs are supposed to connect at the same level:

https://up.codes/viewer/maryland/ipc-2018/chapter/9/vents#912.1.1

Of course, that seems like it might be difficult to address now, and I'm not sure how much of a problem it would be.

Cheers, Wayne

 

[HilltopRehab]

So can you update your diagram to show the joists under the hall bath, how many joists the header is carrying, whether the trimmer joists are doubled, and the location of the bearing walls below at each end of the common joist span? I would think you can tell all of that from the opening in the floor system you currently have, with the exception of the details on the trimmer joist under the hall bath, so that may have to be left unspecified.

Attached is a drawing with more detail. The gray lines indicated the bearing wall below on this end of the joists, and I've noted the other end being 3 feet away in the direction of "down" in the image. The trimmer joists are doubled.
The hall bath side would be a mirror image opposite the stack. The header is carrying 3 joists.
The builder of the home used 2x3s to support the floor around the closet flange, I assume the same for the hall bath. I used skinnier brown lines to indicate that. There is blocking between the bearing wall and the 2x6 wall containing the stack.
The red pipe is the CI, black are the copper lav and shower drains.

Do you know if the hall bath WC is separately vented or wet vented by the hall bath lav or tub/shower? Because if it is relying on the stack for venting, then both WCs are supposed to connect at the same level:

https://up.codes/viewer/maryland/ipc-2018/chapter/9/vents#912.1.1

Of course, that seems like it might be difficult to address now, and I'm not sure how much of a problem it would be.

Cheers, Wayne

The hall bath WC is not separately vented from what I can see. In fact, both upstairs bathrooms as well as the powder room immediately below them seem to be entirely reliant on the stack vent. Each lav and the shower and tub are wet vented through the closet drains.

 

[wwhitney]

Framing wise, the exterior cantilevered wall is basically unsupported for the 64" length (4 joist bay) of the header for the toilet drains? Do the trimmer joists have some heavier than normal looking connection to the rim joist under the wall? How big is the cantilever (overhang)? This is an arrangement I haven't run across before, so I'm not sure how the opening in the cantilevered floor system should be infilled.

Plumbing wise, the WC vent via the stack can't wet vent the lav, the lav's trap is much higher and needs a vent at that level. So the lav needs a dry vent that can recombine with the stack in the ceiling framing or the attic (or it needs an AAV, assuming you are under the IPC). Then if you can fit a wye between the closet flange and the stack, the lav drain can hit that wye to wet vent the WC. And if you flip that wye (compared to the existing) so the lav comes in on the shower side of the WC, then the shower can join the lav drain before the WC, which wet vents the shower from the lav.

I guess for the hall bath it would be simplest to leave it as is for now, but to similarly address the venting when it is next remodeled.

Cheers, Wayne

 

[HilltopRehab]

Framing wise, the exterior cantilevered wall is basically unsupported for the 64" length (4 joist bay) of the header for the toilet drains?

Sorry I gave that a confusing description - it’s actually a total of 3 joist bays, the mirror axis is not the 2x6 wall. My drawing isn’t to scale. The hall bath closet flange is right up against the doubled trimmer joist, which still does make for a strange cantilever setup. I would think the builder could have done the same in the master bath, but I wasn’t there in 1958 either.

How big is the cantilever (overhang)?

The overhang is 10” - measured from the edge of the bearing wall top plate to the face of the rim joist.

Plumbing wise, the WC vent via the stack can't wet vent the lav, the lav's trap is much higher and need a vent at that level. So the lav needs a dry vent that can recombine with the stack in the ceiling framing or the attic (or it needs an AAV, assuming you are under the IPC). Then if you can fit a wye between the closet flange and the stack, the lav drain can hit that wye to wet vent the WC. And if you flip that wye (compared to the existing) so the lav comes in on the shower side of the WC, then the shower can join the lav drain before the WC, which wet vents the shower from the lav.

Thank you for breaking it down like this, it’s starting to click and make sense for me.
I could do an AAV, only reason I might try to avoid it would be to retain as much space under the lav as possible - it’s already going to be a very small vanity.

Dry venting the lav up to the attic to join the stack is doable, but being on an exterior 2x4 wall complicates things in terms of insulation. Of course I’m already thinking about recessing a small medicine cabinet against foam board in that wall so maybe I really should be thinking about furring it out to 2x6... alternative I’m considering is a corner vanity and perhaps then I could triangulate the corner wall all the way to the ceiling to hide the vent inside. Hm.

 

[wwhitney]

Dry venting the lav up to the attic to join the stack is doable, but being on an exterior 2x4 wall complicates things in terms of insulation. Of course I’m already thinking about recessing a small medicine cabinet against foam board in that wall.

Two options for that. If the bottom of the medicine cabinet rough framing cavity is at least 10" above the sink flood rim, then you can bring the vent up and hit an elbow as high as possible. (10" = 6" required above the flood rim ; 2" OD for a 1.5" vent pipe; 1.5" for a 2x4 sill on your framed opening; and 0.5" wiggle room. A little more would be nice, say 11" or 12").

Or you can put the lav san-tee off center from the sink, and then the vent can start jogging immediately above the san-tee at a 45 degree angle. You'd have to drill angled holes through a stud or two, which is why it would be nice to put the lav san-tee off center. You'd need to make allowances for the extra trap arm piping in your vanity cabinet (e.g. make one of the drawers shorter if necessary).

Cheers, Wayne

 

[Tuttles Revenge]

I would suggest a redo where the toilet and the sink trade locations. A pony wall built between the sink and the shower and glass on top of that about 42" up.

 

[wwhitney]

I would suggest a redo where the toilet and the sink trade locations.

In which case, how would you handle the toilet drain and the 2x10 joist framing?

Cheers, Wayne

 

[Tuttles Revenge]

I thought I see the Gray lines as the joists parrelel with the plumbing. Doh..

 

[Tuttles Revenge]

It looks as tho theres room to insert a 3x2 street wye between the hub and the flange. Run 2" parallel with the joists then run 1.5 to the lav, even could potentially offset to reuse the existing holes. or sister on patches and drill thru those (engineers have come up with some crazy easy fixes for that on our projects). Even if the toilet moves slightly forward, either rough it in at 14" and buy a toto 1 pc with 14" unifit.. or pad the wall out just behind the toilet..

 

[Jeff H Young]

Tuttles revenge plan looks great. Id try to use existing lav holes which might mean doing that in dwv copper. street wye and possibly a street 1/4 bend on w/c

 

[Tuttles Revenge]

It would be easy to 90 / 90 after the closet flange to reuse the existing holes. I wouldn't bother trying to install copper drains rather just enlarge the existing as needed and beef up the joists as needed.

We had a job where the original plumbing was lead notched 3" into the joists. The engineer had the framer add several feet of 2x4 either under or over the notches as a repair. *I am not an engineer so that is not advice on how to fix the framing, but a suggestion that an engineer can likely design a fix for that small hole if its even necessary.