Single or Double Wye

[heybeats]

Hey Folks,
Just remodeling my bathroom and moving some fixtures around. And just need some advice about wye's and venting

I am needing to know if I should use a (2) single wye (1) double wye for the following situation

Scenario:
1. bath tub removed and shower pan being installed. The original shower drain line is 1.5" and looking at it its traveling to the right of the 3" drain

2. need to install a 2" drain, and due to the shower pan drain location and it needs to travel to the left of the 3" drain.

3. A toilet exists as well. Its not visible in the picture.
Question:
1. Is it ok to install a 2nd wye as pictured below? Or should I use a double wye?

2. if I installed (2) separate wye, will I also need to somehow install a vent for the shower as well?

The picture shows the (1) wye that has the sink drain connected to the 3" drain along with the toilet. In this case, should I cut off the existing wye and add a double wye? Or am I ok to cut the 3" drain and add an additional wye to accommodate the shower drain?

FYI what is marked NGF is not connected to the 3" drain but it looks like it in the picture.

***The 2nd picture shows the vent. I did mess up on the horizontal vent, it's not high enough. I will be cutting it and raising the horizontal vent so that it's 6 inches higher than the sink fixture. The picture was taken before I put the last connecting pipe.

 

[wwhitney]

In the US, you'd typically bring the shower drain in downstream of the sink connection. That allows the sink to wet vent the WC and the shower. Fixture drains need to be vented before or as they connect to another drain, so you wouldn't connect the shower and the WC before either one is vented.

But I don't know Canadian wet venting rules, could be different.

Cheers, Wayne

 

[Sponsor]

 

[heybeats]

In the US, you'd typically bring the shower drain in downstream of the sink connection. That allows the sink to wet vent the WC and the shower. Fixture drains need to be vented before or as they connect to another drain, so you wouldn't connect the shower and the WC before either one is vented.

But I don't know Canadian wet venting rules, could be different.

Cheers, Wayne

Below is the newly revised plan. Is this what you are referring to? The current wye that is plumbed at the moment for sink drain will likely need to be moved a little so that I can fit another one just downstream of it.

 

[wwhitney]

Yes, that arrangement would be allowed by one of the US codes, the IPC. The other main US code, the UPC, would require that the shower and sink join each other before joining the WC. Which would be possible for you if the "NFG" pipes are going away (what is that about, anyway?) and you could run the shower trap arm on the other side of the WC drain.

A double wye is a possibility, with one large caveat: I would say the barrel of the wye has to be sloped at 3/8" per foot fall instead of the usual minimum 1/4" per foot fall. That's because with a flat double wye, the side inlets will have only 70% of the fall the straight path has, so increasing the fall of the straight path ensures that the side inlets have sufficient slope. But there's some controversy over whether this is allowed or a good idea, so it's probably best to avoid if possible. It's fairly difficult to get the two side inlets at exactly the same elevation, for example.

You might consider cutting back the 3" drain to beyond the current sink wye. That should allow you to run all the drains at more typical angles that are parallel or perpendicular to the wall, avoiding the extra little elbows your current sink wye connection requires, for example.

Cheers, Wayne

 

[heybeats]

Yes, that arrangement would be allowed by one of the US codes, the IPC. The other main US code, the UPC, would require that the shower and sink join each other before joining the WC. Which would be possible for you if the "NFG" pipes are going away (what is that about, anyway?) and you could run the shower trap arm on the other side of the WC drain.

A double wye is a possibility, with one large caveat: I would say the barrel of the wye has to be sloped at 3/8" per foot fall instead of the usual minimum 1/4" per foot fall. That's because with a flat double wye, the side inlets will have only 70% of the fall the straight path has, so increasing the fall of the straight path ensures that the side inlets have sufficient slope. But there's some controversy over whether this is allowed or a good idea, so it's probably best to avoid if possible. It's fairly difficult to get the two side inlets at exactly the same elevation, for example.

You might consider cutting back the 3" drain to beyond the current sink wye. That should allow you to run all the drains at more typical angles that are parallel or perpendicular to the wall, avoiding the extra little elbows your current sink wye connection requires, for example.

Cheers, Wayne

Thanks Wayne. The NFG pipes are the 1.5" drain pipe that was from the bathtub. I haven't pulled it out yet just sitting there willy nilly taking up space. Ill take your advice on the cutting back of the wye, the original plumbers plumbed it that way and I was just trying copy it.

I am not sure if I can join the shower and sink on the "left" side (where the NFG pipe is) because there is a joist in the way, that is why I wanted to run it on the right side.

However, the original setup was that the water closet was the furthest away and the tub drain and sink drain were tied in together with a sanitary tee.

With that being said, the joist is 2x10 and I could possibly drill a hole so that I can run a piece of pipe across. I have to check and see if my code allows for that.

Some background information. The shower pan is technically in the exterior wall, the shower sticks out from the house. Just below the shower pan there is a metal soffit with insulation. I don't have clearance to drop the p trap low enough and run it under the joist.

 

[wwhitney]

However, the original setup was that the water closet was the furthest away and the tub drain and sink drain were tied in together with a sanitary tee.

Just to be clear, connection order is not the same as distance. The WC could be farthest from the stack below, but if the first joint on the WC drain is where the combined lav and shower drain come in (because they've already joined), then I would say the WC is the downstream-most fixture, and the lav/shower are the two upstream-most fixtures.

Cheers, Wayne

 

[heybeats]

Sorry I don't want to be annoying here but I want to make sure I am understanding this.

Below is a picture of the proposed drawing based on your statement (code dependent) for joining shower and sink drain together. This was how it was before with the tub drain (where you saw the NFG pipe sitting there willy nilly). So its safe to assume that I can go as per the drawing so long that I am permitted to drill 1 hole through the floor joist to make the connection happen?

 

[wwhitney]

That layout meets the two main US codes, assuming you use the correct fittings and pipe sizes.

On drilling a 2x10 (D = 9.25"), US codes would allow a hole of size D/3, so you could drill a 2-3/4" for a 2" pipe. In one thread one poster from a different part of Canada said they were limited to D/4, which wouldn't allow one to drill a 2x10 for a 2" pipe. If the hole size is a concern, then a perpendicular hole is better, assuming you can fit a LT90 between the joist and the wall.

If you are redoing most of the 3" pipe, you may be able to avoid taking the shower drain through the joist. I.e. the joist bay may be wide enough for a 3x3x2 wye plus a street 45 in an "upright wye" pattern (two inlets are parallel) to bring the lav + shower drain into the WC drain.

How does the 3" WC drain get through the joist? From the picture it looks as if a huge section is cut out, as it crosses the joist at such an acute angle.

Cheers, Wayne

 

[Reach4]

The distance traveled from the shower p-trap to the bathroom sink area is important. I don't know what your max is.

 

[heybeats]

There is a 22.5 fitting and it connects to a 45 and drops down. The 3" pipe runs at an angle.

If you look at the last one, you will see that white duct and the insulation, that is where the shower is.

"If you are redoing most of the 3" pipe, you may be able to avoid taking the shower drain through the joist. I.e. the joist bay may be wide enough for a 3x3x2 wye plus a street 45 in an "upright wye" pattern (two inlets are parallel) to bring the lav + shower drain into the WC drain."

- i don't want to be asking for too much here but is it possible to do a quick drawing so I can understand this layout?

 

[heybeats]

The distance traveled from the shower p-trap to the bathroom sink area is important. I don't know what your max is.

The distance is about 5 feet. Which is what was there before and what is going to be there now. The only difference is that the P trap from where the bathtub was located and the new shower pan is just a few inches which puts it on the other side of the joist

 

[Reach4]

The distance is about 5 feet. Which is what was there before and what is going to be there now. The only difference is that the P trap from where the bathtub was located and the new shower pan is just a few inches which puts it on the other side of the joist

http://www.bccodes.ca/BCPC_Update_01.16.pdf page "82" says 2.4 meters max for 2 inch, so you have plenty of margin.

 

[wwhitney]

I don't have clearance to drop the p trap low enough and run it under the joist.

Ah, your photo with the white dryer hose makes the situation clearer to me. (I can't quite place the next two photos.) The above statement is an issue, as all the discussion so far has been about layouts in a single horizontal (sloped 2% +) plane, and your current WC drain is under the joists.

Anyway, let me describe again the last layout option, if it's not clear I can make a drawing. And I'm not saying this is the best option, just something to consider. With reference to the picture with the white dryer hose, you could do this, starting at the closet flange: hit a 45 pointed towards the left, then a LT 90 to turn towards the camera. This puts the WC drain on the left side of the joist bay, at an elevation to be determined by other concerns. After the p-trap and an elbow, the shower drain runs parallel to the WC drain, with its center line just a bit above the WC drain. The minimum horizontal distance between them is determined by later considerations, see below.

Then when they are both far enough down the joist bay, the lav drain joins the shower drain, likely with a flat combo (if it's coming in from the direction perpendicular to the joists). The height of the lav and shower drains at this point could be just below the joists, or it could be at an elevation where you can drill a hole through the joist for the lav drain while leaving the necessary unmolested thickness at the bottom of the joists (2" in the IRC).

Now that the lav drain has joined the shower drain, the combined drain can join the WC drain. The shower/lav drain has its centerline a bit above the WC center line (maybe 1/4"), and it hits a flat 45 (likely street) pointed towards the WC drain (turned down a hair if necessary), and then a 3x3x2 wye in the WC drain. Space for those two fittings determines the minimum spacing between the parallel drains; using a street 45 and wye would be efficient.

Now that everything is combined and vented, you can use whatever changes of direction, elevation, etc to join up with the existing vertical 3" drain in an efficient matter.

Cheers, Wayne

 

[heybeats]

Ah, your photo with the white dryer hose makes the situation clearer to me. (I can't quite place the next two photos.) The above statement is an issue, as all the discussion so far has been about layouts in a single horizontal (sloped 2% +) plane, and your current WC drain is under the joists.

Anyway, let me describe again the last layout option, if it's not clear I can make a drawing. And I'm not saying this is the best option, just something to consider. With reference to the picture with the white dryer hose, you could do this, starting at the closet flange: hit a 45 pointed towards the left, then a LT 90 to turn towards the camera. This puts the WC drain on the left side of the joist bay, at an elevation to be determined by other concerns. After the p-trap and an elbow, the shower drain runs parallel to the WC drain, with its center line just a bit above the WC drain. The minimum horizontal distance between them is determined by later considerations, see below.

Then when they are both far enough down the joist bay, the lav drain joins the shower drain, likely with a flat combo (if it's coming in from the direction perpendicular to the joists). The height of the lav and shower drains at this point could be just below the joists, or it could be at an elevation where you can drill a hole through the joist for the lav drain while leaving the necessary unmolested thickness at the bottom of the joists (2" in the IRC).

Now that the lav drain has joined the shower drain, the combined drain can join the WC drain. The shower/lav drain has its centerline a bit above the WC center line (maybe 1/4"), and it hits a flat 45 (likely street) pointed towards the WC drain (turned down a hair if necessary), and then a 3x3x2 wye in the WC drain. Space for those two fittings determines the minimum spacing between the parallel drains; using a street 45 and wye would be efficient.

Now that everything is combined and vented, you can use whatever changes of direction, elevation, etc to join up with the existing vertical 3" drain in an efficient matter.

Cheers, Wayne

I lost you right around here.
Then when they are both far enough down the joist bay, the lav drain joins the shower drain, likely with a flat combo (if it's coming in from the direction perpendicular to the joists). The height of the lav and shower drains at this point could be just below the joists, or it could be at an elevation where you can drill a hole through the joist for the lav drain while leaving the necessary unmolested thickness at the bottom of the joists (2" in the IRC).

Now that the lav drain has joined the shower drain, the combined drain can join the WC drain. The shower/lav drain has its centerline a bit above the WC center line (maybe 1/4"), and it hits a flat 45 (likely street) pointed towards the WC drain (turned down a hair if necessary), and then a 3x3x2 wye in the WC drain. Space for those two fittings determines the minimum spacing between the parallel drains; using a street 45 and wye would be efficient.

I wish I had better pictures, as I am not home at the moment. But you can see the angle that this 3" pipe is running. at the end of the run, where the current wye is, there is a 22.5 fitting, followed by a short piece of pipe, that in turn is connected to a 45 and it drops down to the floor below.

Sorry for the mess, again that long 1.5" pipe on the far left is NFG and not connected.

 

[wwhitney]

OK, I crudely marked up your last photo with the possible layout (slightly tweaked from my textual description). A break in the line is a solvent weld connection, and so when two fittings are draw next to each other, one side of the joint has to be a street end. Green is 3" WC, red is 2" shower, blue is sink, either 1-1/2" or 2" depending on what your code requires for wet venting (here in the US, IPC would be 1-1/2", UPC would be 2").

A few caveats:

- I'm not clear on where exactly the combined 3" drain turns downward, I made a guess (topmost end of green line in picture). It would be nice to use only a 45 on the combined drain (as drawn), but depending on where the drain turns down, what the existing elbows are and how far you can easily cut it back, and how much space the two wyes take up, you might need more bends so the outlet of the final wye can be closer to the top of the picture.

- Another way to get more space for the two wyes would be to jog the lav drain in the wall, towards the bottom of the picture

- I don't show the 45 just below the closet flange as I'm basically sketching in 2D. Likewise the vertical bits in the wall.

- The shower line passes under the closet flange or the angled vertical segment of the WC fixture drain. If necessary you can move it to the left to clear that piping, by jogging it with a pair of 22.5s or 45s. Or if you have room with the lav drain, adding a pipe segment between the two wyes.

- The shower drain, from the trap outlet to the middle of the red wye, is the shower trap arm. That is limited in length to 2.4m per Reach4, and it is limited in fall to one pipe diameter, 2". It would be nice to have both wyes and the blue 45 just under the joists. Hopefully rising no more than 2" from there, the p-trap would be high enough to still have some insulation between it and the metal exterior soffit. If not, you can raise everything around 4", which would allow the lav drain to go through a hole in the joists while maintaining 2" solid wood at the bottom of the joist (or whatever your requirement is), and the combined green drain could drop down after the final wye. [Although if the lav drain has to be 2" under your code for wet venting, raising everything defeats the purpose of this layout, which was to avoid drilling the joist for a 2" pipe, so you could just go back to having the shower drain in the other joist bay.]

Cheers, Wayne

 

[heybeats]

OK, I crudely marked up your last photo with the possible layout (slightly tweaked from my textual description). A break in the line is a solvent weld connection, and so when two fittings are draw next to each other, one side of the joint has to be a street end. Green is 3" WC, red is 2" shower, blue is sink, either 1-1/2" or 2" depending on what your code requires for wet venting (here in the US, IPC would be 1-1/2", UPC would be 2").

A few caveats:

- I'm not clear on where exactly the combined 3" drain turns downward, I made a guess (topmost end of green line in picture). It would be nice to use only a 45 on the combined drain (as drawn), but depending on where the drain turns down, what the existing elbows are and how far you can easily cut it back, and how much space the two wyes take up, you might need more bends so the outlet of the final wye can be closer to the top of the picture.

- Another way to get more space for the two wyes would be to jog the lav drain in the wall, towards the bottom of the picture

- I don't show the 45 just below the closet flange as I'm basically sketching in 2D. Likewise the vertical bits in the wall.

- The shower line passes under the closet flange or the angled vertical segment of the WC fixture drain. If necessary you can move it to the left to clear that piping, by jogging it with a pair of 22.5s or 45s. Or if you have room with the lav drain, adding a pipe segment between the two wyes.

- The shower drain, from the trap outlet to the middle of the red wye, is the shower trap arm. That is limited in length to 2.4m per Reach4, and it is limited in fall to one pipe diameter, 2". It would be nice to have both wyes and the blue 45 just under the joists. Hopefully rising no more than 2" from there, the p-trap would be high enough to still have some insulation between it and the metal exterior soffit. If not, you can raise everything around 4", which would allow the lav drain to go through a hole in the joists while maintaining 2" solid wood at the bottom of the joist (or whatever your requirement is), and the combined green drain could drop down after the final wye. [Although if the lav drain has to be 2" under your code for wet venting, raising everything defeats the purpose of this layout, which was to avoid drilling the joist for a 2" pipe, so you could just go back to having the shower drain in the other joist bay.]

Cheers, Wayne


View attachment 70398

thank you for taking the time to explain this to me. I really appreciate it!

 

[Reach4]

Heybeats: you might want to screw and glue some 2x4 pieces matching top of the joists on the right of your pix. That will get you something to support the new wood, and give you a place to screw it. That may be easier than uncovering half of the existing joist, and be stronger.

Where you have fragments of the old board still there, that could serve as a guide. To prevent glue that oozes out from sticking to something like the fragments, you could put a bit of Saran Wrap in place under the fragments that you will be ripping out.

 

[heybeats]

Heybeats: you might want to screw and glue some 2x4 pieces matching top of the joists on the right of your pix. That will get you something to support the new wood, and give you a place to screw it. That may be easier than uncovering half of the existing joist, and be stronger.

Where you have fragments of the old board still there, that could serve as a guide. To prevent glue that oozes out from sticking to something like the fragments, you could put a bit of Saran Wrap in place under the fragments that you will be ripping out.

Thanks Reach4. It was a real treat to get those subfloors removed. I had to work quick to remove the subfloors as the tenants did not want too much noise that day =/

I do agree with your plan as it was similar as what I had in mind for replacing the subfloor. I am planning on cleaning up the cuts and removing the rest of the bits. Ill keep the flooring on the right side. Some of the 2x 4 will be mounted vertically on both sides of the joist and another 2x4 to on top of the vertical pieces so that I have more of a surface area to drill the new subfloor.

I will need to use my oscillating tool and get the rest of the plywood bits off from under the sill plate and mount some 2x4 as well to support the subfloor.