Shower drain help!

[BostonDIYer]

Hello,

New to this forum and looking for someone who can give some advice on how to best handle muly current plumbing conundrum.

I had to recently demo a shower because I was dumb enough to donate thousands of dollars to a couple of knuckleheads who sold me a 2-year tiled shower. It's a 2-year shower because it leaks into your second floor ceiling after 1-year and then you learn it's actually the failed waterproofing that caused it so you tear it out in year 2!

So, I am progressing along swimmingly and am fixing all sorts of crap they should have caught/done themselves. I am officially into the subfloor and therefore have to replace the shower drain. I am struggling to figure out what the heck exactly to do with this thing.

Let me start by saying the previous drain was not a problem. Also, excuse my poor cutting job. That was my first attempt at using an inside pipe cutter. Anyway, the plumbing seemed to do it's job just fine previously. But, the house and plumbing are coming up on 20 years old and while I am in here, I may as well update whatever needs updating.

That said, I also came across what appears to be a small piece of cpvc (maybe?) connected to what I believe is just plain old PVC. I did not know there were different types of PVC until about 5 minutes ago but I did learn the cement for cpvc needs to be different.

Here are my questions...
I would like this drain to remain roughly exactly where it was previously. This is my first time working with PVC but put 10 years in the trades so I know how to get by. Given the importance of this step, I want to get this exactly right. What would the preferred path forward be with what I have going on in this picture? FWIW, everything past the p-trap seems to be sloped correctly, venting in the right place, etc. What should I do to get a well performing drain back in place so I can begin closing up the subfloor?

Next and maybe a very noob question but why no primer on most of these other connections? Were the plumbers actually that neat or should I be able to crack these joints open with a couple or wrenches? Sounds funny as I type it but the joints do look a bit like they could be mechanically connected and not cemented.

Last question, in the picture with the two pipes coupled together, when I wrap my hand around that and give it a slight wiggle, it feels as though the coupling has a little bit of play in it. The water stains below it I don't *believe* are from this drain pipe and are instead from the non-waterproof shower curb that was there previously. However, it feels like this connection could be more solid than it actually is. Should I cut it out and splice in a fresh piece with new primer and cement?

P.s. you all can ignore the pex for now. I am probably going to clean that up a bit as well since they also failed to add pressure balance loops for the body jets. Good time for me to get rid of some of these mostly unnecessarily buried fittings.


Thanks in advance!

-- Chris

 

[MicEd69]

FWIW, everything past the p-trap seems to be sloped correctly, venting in the right place, etc.

Oops, that isn't quite correct. You cannot, by any code, go up from a P-trap and then back down before you vent the drain line. That results in a S-trap.

There is a clear primer that can be used, and some unscrupulous plumbers do install PVC piping without a primer. So, I'm not sure what is the case here.

Also, while there is much debate about using a Sanitary tee as a dry vent, which I think is acceptable per IPC code language at least, others insist that a dry vent needs to be a wye or a combo fitting.

So, at the very least, you need to drop that P-trap so that the slope from the trap weir is 1/4" per foot towards the drain. And depending on which camp you think is correct, or more importantly which camp your inspector is a member of, you may need to change that Sanitary tee on its back to a combo fitting for the vent.

 

[BostonDIYer]

Oops, that isn't quite correct. You cannot, by any code, go up from a P-trap and then back down before you vent the drain line. That results in a S-trap.

There is a clear primer that can be used, and some unscrupulous plumbers do install PVC piping without a primer. So, I'm not sure what is the case here.

Also, while there is much debate about using a Sanitary tee as a dry vent, which I think is acceptable per IPC code language at least, others insist that a dry vent needs to be a wye or a combo fitting.

So, at the very least, you need to drop that P-trap so that the slope from the trap weir is 1/4" per foot towards the drain. And depending on which camp you think is correct, or more importantly which camp your inspector is a member of, you may need to change that Sanitary tee on its back to a combo fitting for the vent.

Thanks for the quick reply!

I have just about two inches of clearance below the bottom of that existing p-trap before I hit the sheetrock below. Is this enough clearance in your opinion? The bottom of the horizontal yellow-ish piece (Is this cpvc or just old and discolored? Does it matter either way?) is just about 4 inches above the sheetrock below it.

Regarding the plumbing vent, I don't believe the guys that did most of this mess changed up the original vent at all. Unless you see a major risk there, I will probably just leave it be.

 

[Twowaxhack]

It’s not cpvc, it’s pvc. You have an illegal S-trap. The reason why it’s been working is because showers don’t have stoppers like a bathtub where a large volume of water could flow at once. If your drain started to clog a little and started filling up, it would siphon. This can compromise the trap seal and you could get sewer gas in the living space.

Pvc joints shouldn’t wiggle, so that’s a bad joint.

I’ve done some tests with primer and without. There are one step cements that some codes will accept. I’ll suggest that you follow directions on the can.

 

[Ludington]

Could he come over from the top of the p trap, make the corner teeing nto the vent , and then down into the drain ? Not sure if there is enough room in the vent to get a t and then the elbow back to the drain. That would get rid of the s trap, without getting into the ceiling.

 

[BostonDIYer]

It’s not cpvc, it’s pvc. You have an illegal S-trap. The reason why it’s been working is because showers don’t have stoppers like a bathtub where a large volume of water could flow at once. If your drain started to clog a little and started filling up, it would siphon. This can compromise the trap seal and you could get sewer gas in the living space.

Pvc joints shouldn’t wiggle, so that’s a bad joint.

I’ve done some tests with primer and without. There are one step cements that some codes will accept. I’ll suggest that you follow directions on the can.

Ok, thank you for the information!

So, I will have to tear out the S-trap and replace it with a proper P-trap. Would the best way to do this be to cut it back to that discolored piece on the arm and 90 right into that? Basically, cut the mess off, create a new joint a coupling, extend with a fresh piece of straight PVC then 90 down into the trap to place the inlet side of the P-trap where I need it to be in the shower. Finally, just stub up through the floor to the proper height? Is it that simple?

 

[BostonDIYer]

Maybe to simplify what I'm asking, can I simply remove everything between the discolored piece and the 90 degree elbow coming off the P-trap? That should lower the trap a bit. Obviously I will have to move that pex to make some room.

 

[MicEd69]

I have just about two inches of clearance below the bottom of that existing p-trap before I hit the sheetrock below. Is this enough clearance in your opinion?

No, to bottom of the P-trap is going to be about 2" below the top of the sheetrock or 1 1/2" below the ceiling of the room below with your current drain line elevation. I'm not sure if this is a second-floor bathroom or if this is over a finished basement or if this is over a basement storage area. If you can live with that pipe protruding into the ceiling in the room below, that would be the easiest repair.

Without actual dimensions, it's a little difficult to say for sure, but you may be able to fix this correctly by using 22.5-degree fittings. One determining factor is you need to hit the hole in the floor joist just after the vent.

You may be able to raise the vent Sanitary tee by using a pair of street 22.5-degree fittings right at the joist hole. That will move the vent connection higher and further away from the hole in the joist. That will allow you to lower the existing P-trap and by maintaining a 1/4" per foot slope from the P-trap weir to the vent connection, you will be good. Note I'm not sure you have the room to do this. The flat 90 can be replaced with a short radius 90 which will give you a little more room between the existing joists. And while I'm not sure, I think you will still be able to get the vent line to line up with the vertical vent pipe with appropriate fittings.

 

[BostonDIYer]

Yeah sorry for not specifying. This is a third floor bathroom. The sheetrock below is the entrance to a 2nd floor bedroom and dropping into it won't be a viable option. I'm in a townhouse which is in a building with 5 others just like it to give you a general idea of what we are dealing with.

I can give some exact measurements. What should I use as a reference point for the heights of everything? Is measuring up from the sheetrock ceiling ok? For the connectors, are measurements to the center of the joint/connector ok?

Taking a step back for one moment, these are standard 16" joist bays use 10" lumber. I guess I am trying to understand what they screwed up so badly besides raising the height of the arm before dropping down into the trap. Would something like the attached work? The trap would be touching the ceiling which seems not great but it looks like I would achieve the P-trap configuration. Is the issue now that the trap weir and center of vent fitting are at roughly the same height?

Thank you all for the responses, by the way. Learning a ton just looking into some of the feedback you've already provided. Very helpful!

 

[Twowaxhack]

Yeah sorry for not specifying. This is a third floor bathroom. The sheetrock below is the entrance to a 2nd floor bedroom and dropping into it won't be a viable option. I'm in a townhouse which is in a building with 5 others just like it to give you a general idea of what we are dealing with.

I can give some exact measurements. What should I use as a reference point for the heights of everything? Is measuring up from the sheetrock ceiling ok? For the connectors, are measurements to the center of the joint/connector ok?

Taking a step back for one moment, these are standard 16" joist bays use 10" lumber. I guess I am trying to understand what they screwed up so badly besides raising the height of the arm before dropping down into the trap. Would something like the attached work? The trap would be touching the ceiling which seems not great but it looks like I would achieve the P-trap configuration. Is the issue now that the trap weir and center of vent fitting are at roughly the same height?

Thank you all for the responses, by the way. Learning a ton just looking into some of the feedback you've already provided. Very helpful!

Yes, what you’re showing in this pic needs to happen.

 

[MicEd69]

It's hard to tell from pictures, so I was just using dimensions of fittings for the elevation calcs.

But your latest picture appears to show that the P-trap in your hand at the elevation of the discolored drain line will just touch the top of the drywall. If that is the case, that will work. The P-trap will be a little higher at the drain location as the drain line needs to slope 1/4" per foot towards the drain. The only issue will be if you can get around the water line.

 

[havasu]

(moderator note...I've taken the liberty of enlarging your pictures for us old guys on here. Once you upload an image, select full image versus thumbnail pic)

 

[BostonDIYer]

It's hard to tell from pictures, so I was just using dimensions of fittings for the elevation calcs.

But your latest picture appears to show that the P-trap in your hand at the elevation of the discolored drain line will just touch the top of the drywall. If that is the case, that will work. The P-trap will be a little higher at the drain location as the drain line needs to slope 1/4" per foot towards the drain. The only issue will be if you can get around the water line.

This sounds like a plan! Those pex lines are 100% in the way but I had planned on moving them anyway. I'm not crazy about the buried 90-degree fittings when a simple sweep should do, less connections, less potential for failure. I picked up a couple of the plastic 90 degree sweeps to replace what you see in the pics. I have about 102" from the copper pipe in the picture to the shower diverter valves. This will give me about 18" of slack to support the water lines properly to a joist and get them out of the way of the drain. Pics attached, please let me know if you see any issues with this plan. I can't really speak to why they coupled the line right after connection to the copper, maybe they were running low on pex? Plan is to use a single piece to run from that copper directly to the valves.

(moderator note...I've taken the liberty of enlarging your pictures for us old guys on here. Once you upload an image, select full image versus thumbnail pic)

Ah, will do! Sorry about that! Will do this going forward!

 

[Twowaxhack]

I suggest having a professional come in and remove those sharkbites and solder on some adapters.

I recall you saying this in between the 2nd and 3rd floor.

 

[BostonDIYer]

I suggest having a professional come in and remove those sharkbites and solder on some adapters.

I recall you saying this in between the 2nd and 3rd floor.

Ah! I don't know whether to laugh or cry at this point lol. Of course that's also not correct! And yes, it is indeed the 3rd floor bathroom and is sitting over a 2nd floor bathroom and bedroom.

 

[Twowaxhack]

If your ptrap needs a little more room you can install an access panel on the ceiling and get at minimum another 1/2” of space and we have also furred the ceiling down 2” and created an access panel.

It doesn’t look the best but it solves the plumbing problem in an inexpensive way.

 

[BostonDIYer]

I think it's time for a new plan. The drain side of this pipe does not actually seem to slope correctly as I previously assumed. In fact, it appears the mess I have under the old shower may be raising/supporting the drain side a little bit. It looks as though the penetration in the joist just before the vent tee is about 1/2" higher than the subsequent joist which is closer to the actual drain pipe. I don't have access to the joists further downstream to confirm but I would expect this PVC to at least be resting on the bottom of the hole but it is instead being forced to the top of it. This is also the coupler that appears to have a little bit of play in it.

If I were to cut this all the way back and start fresh, how would I do this correctly? I would need to cut the vent pipe out too and reattach but should theoretically be able to get all my clearances and measurements correct at that point. I attached another reminder of what exactly this looks like. What's the ideal solution, forget about what's easy and cheap. I would prefer to do this once and not think about it again for the next 20 years.

 

[MicEd69]

As long as the piping between the P-trap and the vent connection is sloped downstream at 1/4" per foot, and the drain line from the vent connection to the drain slopes 1/4" per foot or more downstream, you will be fine. So, if the drain line at the vent connection is at the top of the hole, as long as the lines meet the above slope requirements, you don't have a problem.

But a loose joint is a problem that needs correction.

 

[BostonDIYer]

As long as the piping between the P-trap and the vent connection is sloped downstream at 1/4" per foot, and the drain line from the vent connection to the drain slopes 1/4" per foot or more downstream, you will be fine. So, if the drain line at the vent connection is at the top of the hole, as long as the lines meet the above slope requirements, you don't have a problem.

But a loose joint is a problem that needs correction.

Thanks. I cut everything out back to the loose joint, loaded up on PVC fittings and am planning how to reassemble everything back to code and finally get this drain set so I can move on to the next piece of this project.

If I am hearing you correctly, using a sanitary tee at the vent may not be ok for some. I can swap it out with a combo fitting but I don't believe home Depot has one with a 1.5" connection. Am I good to use a reducer to make this work?

Before I develop my own solution or try to rebuild what was here previously with the correct slopes, if this were your job, how are you dying this bad boy together at this point? Spent all night learning about PVC connections which admittedly does not seem like it should be so complicated but I've read enough people getting it wrong that it has me probably way overthinking this. Also, I'm not married to using that existing joist hole so if it'd be better for me to 90 the drain in its current bay and 90 again to the shower drain and tie the venting in differently, I am all ears!

 

[MicEd69]

OK, your vent has to come off the drain line vertically, or no more than 45 degrees off vertical which is the way your original vent was done. So at least by the pictures, it appears you will have to use the existing vent line and the original path of the drain line. If you do have issues being able to fit the piping layout in your existing space and depending on the elevation of the drain line relative to the shower floor, you possibly could use a 22.5-degree street elbow right at the hole in the joist to begin the turn towards your shower drain. You just need to be sure you can clear the shower floor with the vent line and not drop the angle more than 45 degrees off vertical.

You can get a 2"x2"x1 1/2" combo fitting at a plumbing supply store.



But you can use a 2" combo and bush the branch down to 1 1/2" for the vent line. However, Home Depot does have a 2"x2"x1 1/2" reducing wye, and with a 1 1/2" street 45 on the branch, it might fit better in the space you have than a 2" combo. That is provided you don't want to use a Sanitary tee like you had before. I personally would use a Sanitary tee there, but others would say to use the combo or wye assembly. Home Depot does have a 2"x2"x1 1/2" reducing Sanitary tee.

To install all this, it is just a matter of cutting the pipe to the correct lengths and making sure you have the 1/4" slope from the P-trap weir to the vent connection, and at least a 1/4" per foot slope in the line after the vent to the sewer connection. It may help you to add a few wood pieces between the joists and some shims to help you establish and maintain the slopes.

Dry fit everything but remember once you prime and apply the glue to the joint, the pipe will go farther into the hub of the fitting than it will when it is dry fit. A 2" pipe will go into the hub about 3/4" until it bottoms out in the fitting. So, your dry fit assembly will not fit in your space.

You'll have a few seconds to play with the joint before it sets, and you need to hold the pipe or fitting tight into the hub being glued for around 30 seconds or so, or it will squeeze itself out and you will say bad words.