Convert single drain into 2 standalone vanities

[Tuttles Revenge]

So is your experience that a 45 flange plus a 45 will perform better (clog less) than an offset flange plus a closet bend? That was my intuition, but I don't have any actual experience.

Cheers, Wayne

Yes, the offset flanges create choke points. I've seen some newer ones that appear less bad, but a 45deg flange here would be a no brainer.

The only downside to them is that its hard to get flooring material underneath the part that is closest to inside of the bend. And watch out not to get screws down into that part too!

 

[Mark Kessler]

Thanks guys, yes no clean out have no clue why it is there other than thats all they had on hand at the time.

so question on the 45 flange to 45. Could i use a standard straight flange into a 45 then to a 45, the flange with the 45 looks potentially challenging to install once the tile is in.

 

[Sponsor]

 

[Mark Kessler]

Also, I adjusted the wall to allow the drains and water lines to go straight down as Wayne suggested.

Does the drains look right for the drains and vent? I didn’t adjust the studs in the drawing so refer to the picture of the wall.
I marked in the direction of the santee, also all 1-1/2”

 

[Reach4]

1. I suspect it takes more skill to glue in the 45 degree flange, but if you can do it, 45 flows nicely. I think the discussed offset flange will pass a 3 inch ball and is really not likely to cause a blockage.
2. I suspect that the offset flange many need less notching of the joist in this case. See IMG_1.jpg
3. I think using a 4x3 closet flange next to the joist will take more space than using a 3 inch medium elbow.

 

[wwhitney]

so question on the 45 flange to 45. Could i use a standard straight flange into a 45 then to a 45, the flange with the 45 looks potentially challenging to install once the tile is in.

Yes, you could, but it would interfere with the joist more, not sure it would fit in your existing notch. Also, it would require more height in the joist bay, not sure you have that much height.

If I were installing a 45 flange in a tiled floor, I would figure out my finish floor elevation, add 1/8" for the top of the flange, and use a ring of plywood blocking under the flange itself, screwed to the subfloor (but not into the pipe, as Tuttle notes!), to set the 45 flange at the correct height at the time of glue up. [That could mean cutting the plywood blocking ring into two pieces to install just after gluing, depending.] Then I'd just tile up to the flange, rather than under the flange.

In other words, while the flange height should be just above the finish floor, the finish floor doesn't have to actually run under the flange. Maybe there are some upsides to running the finish floor under the flange that I'm overlooking, however.

Also, I adjusted the wall to allow the drains and water lines to go straight down as Wayne suggested.

I think that was Terry and/or Tuttle, not me.

Cheers, Wayne

 

[WorthFlorida]

It's not always possible to go straight down inside the wall. This was my main bath where I changed to a double sink vanity. Directly below the entire sill plate is a floor trust. This 2" pipe tied into a three inch line running to the right. The builders plumber did it so well that it didn't require the base cabinet to be notched.

 

[Mark Kessler]

1. I suspect it takes more skill to glue in the 45 degree flange, but if you can do it, 45 flows nicely. I think the discussed offset flange will pass a 3 inch ball and is really not likely to cause a blockage.
2. I suspect that the offset flange many need less notching of the joist in this case. See IMG_1.jpg
3. I think using a 4x3 closet flange next to the joist will take more space than using a 3 inch medium elbow.

Thanks, ya I don’t think i am gona have the skill to get that 45deg flange set right. It does appear that the off set will need less notching so I will probably need to go that way…

 

[Reach4]

Thanks, ya I don’t think i am gona have the skill to get that 45deg flange set right. It does appear that the off set will need less notching so I will probably need to go that way…

If you do go with the 3x4 closet bend, you might consider the Sioux Chief 889-GPOM
Push Tite offset flange. Because it does not glue in, you could lift it later and change flooring... not that that happens a lot. But push-in gives easy do-overs.

If you use 3 inch to accept the closet flange, then I would glue.

 

[Mark Kessler]

Yes, you could, but it would interfere with the joist more, not sure it would fit in your existing notch. Also, it would require more height in the joist bay, not sure you have that much height.

If I were installing a 45 flange in a tiled floor, I would figure out my finish floor elevation, add 1/8" for the top of the flange, and use a ring of plywood blocking under the flange itself, screwed to the subfloor (but not into the pipe, as Tuttle notes!), to set the 45 flange at the correct height at the time of glue up. [That could mean cutting the plywood blocking ring into two pieces to install just after gluing, depending.] Then I'd just tile up to the flange, rather than under the flange.

In other words, while the flange height should be just above the finish floor, the finish floor doesn't have to actually run under the flange. Maybe there are some upsides to running the finish floor under the flange that I'm overlooking, however.

- I bought a straight flange and a couple of 45’s, totally won’t work as you predicted.
- thats a good plan for installing the flange with the 45, i still don’t think i can personally do that and it be successful but still need to think on it.
- clearly the offset would be the easiest one to install and as reach4 mentioned appears that it would require less notching

however i have a major joist issues, the first 2 pictures show the butchered joist and half a#&$@!s mini scab which is also butchered.

This is right under the to be new shower, additionally the toilet rough in 13” from the stud which is pretty much center of the joist.

Third picture is the proposed fix showing the small scab removed and green sister added, i would make it as long as possible but probably not much more than shown. Would use PL premium and GRK RSS structural screws. Not sure if that is enough to fix it


I think that was Terry and/or Tuttle, not me.

Cheers, Wayne

Yup, was Tuttle - thanks Tuttle, think that was the best plan…

 

[Mark Kessler]

It's not always possible to go straight down inside the wall. This was my main bath where I changed to a double sink vanity. Directly below the entire sill plate is a floor trust. This 2" pipe tied into a three inch line running to the right. The builders plumber did it so well that it didn't require the base cabinet to be notched.
View attachment 76921

Actually didn’t think of doing that because my vanitys will be furniture like so i think it could be seen but maybe do that part in copper

 

[Mark Kessler]

Also, I adjusted the wall to allow the drains and water lines to go straight down as Wayne suggested.

Does the drains look right for the drains and vent? I didn’t adjust the studs in the drawing so refer to the picture of the wall.
I marked in the direction of the santee, also all 1-1/2”

Any feedback on if this plan (post above on 2/20 @ 2:19pm) for the drains and venting will work? Starting on it right now, thanks!

 

[wwhitney]

Any feedback on if this plan (post above on 2/20 @ 2:19pm) for the drains and venting will work? Starting on it right now, thanks!

The two fittings in the floor joists are not correct. The 90 in the floor should be a long turn 90. And you can't use a san-tee on its back for drainage, so that san-tee in the floor should be a combo.

Otherwise looks fine. The top row of fittings for the vents need to be 6" above the flood rim of the sink, or more. And the 90s there can be any type, but regular quarter bends are most common. Vent 90s are only useful where space is really tight.

Cheers, Wayne

 

[Mark Kessler]

The two fittings in the floor joists are not correct. The 90 in the floor should be a long turn 90. And you can't use a san-tee on its back for drainage, so that san-tee in the floor should be a combo.

Otherwise looks fine. The top row of fittings for the vents need to be 6" above the flood rim of the sink, or more. And the 90s there can be any type, but regular quarter bends are most common. Vent 90s are only useful where space is really tight.

Cheers, Wayne

Thanks, The vent is 6” above the top of the vanity, should have put that in the drawing. i did end up getting a long 90 for that first on in the joist bay, I was just looking at that santee for the second spot and was thinking it didn’t look right.

Just to confirm the is a combo tee correct? https://www.homedepot.com/p/NIBCO-1...ination-Tee-Wye-Fitting-C4812LHD112/100345167

 

[wwhitney]

Just to confirm the is a combo tee correct? https://www.homedepot.com/p/NIBCO-1...ination-Tee-Wye-Fitting-C4812LHD112/100345167

Yes.

 

[Mark Kessler]

Yes.

Perfect, thanks for your help on this

 

[Mark Kessler]

So here is where I am with the notched joist that the flange lands on. The unsupported span of the joist is 140” and i think i can squeak in a sister of at least 120” so that should be good.

So the original joist that is notched will still be err… notched.

1. If I use the offset it will be about 13.5” from the stud (pic shows about 12.5” but it will be further out) which puts the back of the toilet at 1” from the drywall, not bad - I can live with that.

2. If I use a standard flange it will be about 14-1/4” from the stud, 13.75” toilet to dry way too far (don’t you think?)
- I could fir out the wall to fill the gap
- There is a challenge with this approach, there is a HW baseboard on the wall so i will need to either have the drywall wrap around it and maybe use some trim or cut back the cover, flippy thing and the top of the profile so the drywall can be behind it (so the HW baseboard dead ends into it like it should)

3. looks like in either case i would use a standard 90 to a long 90 from the flange, correct?

4. As far as the 3” line to the 3” PVC vent to the copper vent (will cut out the corroded part) can that 3” PVC vent could be 2”? I will be changing that tub drain to a 2” center drain for the 32 x 60 shower.

Thanks and Thoughts?

 

[wwhitney]

2. If I use a standard flange it will be about 14-1/4” from the stud, 13.75” toilet to dry way too far (don’t you think?)

As I suggested, I think using a 14" rough-in toilet is the most elegant solution, as long as you get one that has a different internal geometry for the trap way and doesn't just stick an extra 2" out into the room. Unless you have lots of space in front of the toilet and don't mind it sticking out the extra 2". [That is, some 14" rough-in toilets, I understand, use a mold based on the 12" version and just extend the bowl and/or the tank an extra 2" rearwards.]

If you arrange for the notch in the joist to be entirely unobstructed, and the bottom 3", say, of the joist is uncut, then there is definitely a performance benefit to cutting a tight fitting block to replace the missing wood in the top 3" of the joist. That portion of the joist is under compression for downward loads on the joist, so the block would need to be tight; you can run a metal strap across the block to hold it in place. I think I'd still sister the area with a full depth member ideally at least 3' past the damage on both sides, with the appropriate number of structural screws on each side of the repair.

BTW, on the vent connection, that's the wrong type of rubber coupling, it's only rated for below ground use. You need a fully shielded coupling, they are also shorter in length.

Cheers, Wayne

 

[Mark Kessler]

As I suggested, I think using a 14" rough-in toilet is the most elegant solution, as long as you get one that has a different internal geometry for the trap way and doesn't just stick an extra 2" out into the room. Unless you have lots of space in front of the toilet and don't mind it sticking out the extra 2". [That is, some 14" rough-in toilets, I understand, use a mold based on the 12" version and just extend the bowl and/or the tank an extra 2" rearwards.]

If you arrange for the notch in the joist to be entirely unobstructed, and the bottom 3", say, of the joist is uncut, then there is definitely a performance benefit to cutting a tight fitting block to replace the missing wood in the top 3" of the joist. That portion of the joist is under compression for downward loads on the joist, so the block would need to be tight; you can run a metal strap across the block to hold it in place. I think I'd still sister the area with a full depth member ideally at least 3' past the damage on both sides, with the appropriate number of structural screws on each side of the repair.

BTW, on the vent connection, that's the wrong type of rubber coupling, it's only rated for below ground use. You need a fully shielded coupling, they are also shorter in length.

Cheers, Wayne

Thanks for the comments, that part of the joist is most definitely in shear due to how close it is to the supporting wall.

I plan on putting a 120”sister on which should be more than adequate. I think i mentioned before that a 14” rough in toilet will not work for me, the toilet is bought and is 12”.

As you can see in the drawing below by just using a standard flange in front of the notched joist it puts the toilet about 3” from the drywall, so i will just build out the wall 3”. And it is still within the wall to the right.

It will take a little more time and material because i will need to add blocking for the subfloor to land on, but is a better solution I believe than monkeying around with an offset or 45 flange.

thanks for pointing out the incorrect fitting, that one was existing from the demo but I probably would have reused it if you hadn’t pointed that out. Incidentally, why does it need to be shielded, it’s not like a screw couldn’t go through it…

 

[wwhitney]

Thanks for the comments, that part of the joist is most definitely in shear due to how close it is to the supporting wall.

I guess I'm not clear on where the supporting wall is located, I would think a rule of thumb would be that the shear zone at the support extend horizontally from the support an amount equal to the joist depth. But perhaps I'm off by a factor of 2?

I think i mentioned before that a 14” rough in toilet will not work for me, the toilet is bought and is 12”. [. . .] As you can see in the drawing below by just using a standard flange in front of the notched joist it puts the toilet about 3” from the drywall, so i will just build out the wall 3”.

You mentioned you didn't want to use a 14" rough in toilet, not that you had a 12" rough-in toilet on hand already. At the risk of belaboring the point, I suggest looking at the compromises and expense of getting a new 14" rough-in toilet compared to the compromises and expense of building out the wall 3". I.e. be aware of the sunk cost fallacy.

thanks for pointing out the incorrect fitting, that one was existing from the demo but I probably would have reused it if you hadn’t pointed that out. Incidentally, why does it need to be shielded, it’s not like a screw couldn’t go through it…

The shielding is for rigidity, not for fastener penetrations, if subject to that a separate nail plate would be required. Underground pipe is generally fully supported by soil, so the joint itself apparently is not required to be so rigid. But above ground supports are less frequent, and the rubber coupling needs the full metal shield to be rigid enough for the long haul.

Cheers, Wayne

 

[Mark Kessler]

I guess I'm not clear on where the supporting wall is located, I would think a rule of thumb would be that the shear zone at the support extend horizontally from the support an amount equal to the joist depth. But perhaps I'm off by a factor of 2?

- The notch for the toilet starts at about 23” from a support of a 14o” joist, definitely in the shear zone. But there are other notches where the bending moment is more in play, it doesn’t really matter though as I will be sistering an almost full length full width joist, I will probably fill in the notch as you mentioned for extra insurance, a properly sized steel strap on top would be beneficial as well but I am not going to go that far…

You mentioned you didn't want to use a 14" rough in toilet, not that you had a 12" rough-in toilet on hand already. At the risk of belaboring the point, I suggest looking at the compromises and expense of getting a new 14" rough-in toilet compared to the compromises and expense of building out the wall 3". I.e. be aware of the sunk cost fallacy.

- I have considered all the compromises, prolly not more than $30 in additional material and my labor is free, maybe 2 hrs max. I have some time so if I can find a 14” that i like i would probably buy it.

I guess what I was really looking for is that the straight flange option is better than an offset as far as performance standpoint and was the better option no matter

The shielding is for rigidity, not for fastener penetrations, if subject to that a separate nail plate would be required. Underground pipe is generally fully supported by soil, so the joint itself apparently is not required to be so rigid. But above ground supports are less frequent, and the rubber coupling needs the full metal shield to be rigid enough for the long haul.

- Thanks.


Cheers, Wayne