Thanks for detail...RV Dump had no vent so I guess it would be 3". Do you know of any diagrams of a similar setup?
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Thanks for detail...RV Dump had no vent so I guess it would be 3". Do you know of any diagrams of a similar setup?
wwhitney
In the Trades
I'm not sure how an RV dump should be plumbed, it might be better/easier to add a 3" vent there and stick with a 2" vent at the bathroom group.
Cheers, Wayne
Cheers, Wayne
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RV dump is just a cleanout cap on one end of a run of pipe that terminates in septic...I guess it could just as well be considered a cleanout so not sure that matters in this case. It is not in use as RV dump now but previous owner used it for that occasionally.
Do you know of any diagrams or images of a similar setup to this:
"Lav vent through the roof, lav drain in the wall, and downstream should be 2" (* see below *)
Lav trap arm can be 1-1/4" or 1-1/2" to a san-tee in the wall, e.g. a 2x2x1-1/2 san-tee.
A tub can use a 1-1/2" trap and 1-1/2" trap arm, which runs up until it joins the 2" lav drain (wet vent). Then the trap arm is limited to 42".
A shower would need a 2" trap and trap arm, or a tub could use a 2" trap and trap arm. Then the trap arm is limited to 60".
The WC and downstream has to be 3", obviously.
The best practice for joining the WC is with a horizontal wye with the WC coming in the branch inlet, e.g. a 3x2x3 wye created with a 2" bushing in the straight inlet for the 2" lav + shower/tub drain. Then the WC closet bend points at a 45 degree angle to the wall to go straight into the wye branch inlet."
Do you know of any diagrams or images of a similar setup to this:
"Lav vent through the roof, lav drain in the wall, and downstream should be 2" (* see below *)
Lav trap arm can be 1-1/4" or 1-1/2" to a san-tee in the wall, e.g. a 2x2x1-1/2 san-tee.
A tub can use a 1-1/2" trap and 1-1/2" trap arm, which runs up until it joins the 2" lav drain (wet vent). Then the trap arm is limited to 42".
A shower would need a 2" trap and trap arm, or a tub could use a 2" trap and trap arm. Then the trap arm is limited to 60".
The WC and downstream has to be 3", obviously.
The best practice for joining the WC is with a horizontal wye with the WC coming in the branch inlet, e.g. a 3x2x3 wye created with a 2" bushing in the straight inlet for the 2" lav + shower/tub drain. Then the WC closet bend points at a 45 degree angle to the wall to go straight into the wye branch inlet."
wwhitney
In the Trades
I don't know of any handy diagrams that would match my description. What additional details are you looking for?
Cheers, Wayne
Cheers, Wayne
I am mainly having trouble seeing the exact parts and set up for this:
"The best practice for joining the WC is with a horizontal wye with the WC coming in the branch inlet, e.g. a 3x2x3 wye created with a 2" bushing in the straight inlet for the 2" lav + shower/tub drain. Then the WC closet bend points at a 45 degree angle to the wall to go straight into the wye branch inlet"
"The best practice for joining the WC is with a horizontal wye with the WC coming in the branch inlet, e.g. a 3x2x3 wye created with a 2" bushing in the straight inlet for the 2" lav + shower/tub drain. Then the WC closet bend points at a 45 degree angle to the wall to go straight into the wye branch inlet"
wwhitney
In the Trades
Ah, OK. Here's another diagram, which is slightly different than the above description, and doesn't address the need for a 3" vent through the roof. Red is the 2" drain coming in from the shower and lav (upstream components not shown), it hits a horizontal 45, and then a 3x3x2 horizontal wye. Green is the 3" drain with the closet bend and closet flange above not shown. And of course, the layout of the lines over the saw cuts is not right, the closet flange should be 12" from the finished wall surface for a 12" rough in WC.
Cheers, Wayne
Cheers, Wayne
wwhitney
In the Trades
BTW, if you need a 3" vent through the roof for this bathroom (which you do if you don't have it anywhere else on this DWV system), I'm not sure any of the layouts I drew are very good. I could try again if you (a) draw an approximate line on your photo showing where you think the thickened slab edge footing is, meaning the area you want to minimize running drains through as much as possible and (b) tell me a little about the wall construction, as far as how difficult it would be to run a 2" pipe horizontally in the walls. I assume you can run a 3" pipe vertically within the wall up through the roof.
Cheers, Wayne
Cheers, Wayne
(a) draw an approximate line on your photo showing where you think the thickened slab edge footing is, meaning the area you want to minimize running drains through as much as possible
see image:
note the 2, 2x4 walls do bring you quite a ways in such that for most of the plumbing it should not be too thick...mainly upon exiting the bldg and of course the venting. I will try to cut out and stay in the green zone but if I have to cut more I will.
(b) tell me a little about the wall construction, as far as how difficult it would be to run a 2" pipe horizontally in the walls. I assume you can run a 3" pipe vertically within the wall up through the roof.
existing 2x4 wall currently has nothing in it but will put in insulation. new 2x4 wall is to run the water lines and I guess in this case additional plumbing. I guess could utilize both walls space if had to.
see image:
note the 2, 2x4 walls do bring you quite a ways in such that for most of the plumbing it should not be too thick...mainly upon exiting the bldg and of course the venting. I will try to cut out and stay in the green zone but if I have to cut more I will.
(b) tell me a little about the wall construction, as far as how difficult it would be to run a 2" pipe horizontally in the walls. I assume you can run a 3" pipe vertically within the wall up through the roof.
existing 2x4 wall currently has nothing in it but will put in insulation. new 2x4 wall is to run the water lines and I guess in this case additional plumbing. I guess could utilize both walls space if had to.
wwhitney
In the Trades
OK, here's a very crude drawing, approximately in the perspective of your photo, and not quite to scale. It's one possibility, not necessarily the best possibility. The layout is governed by a couple principles: (a) keeping the 3" drains near the bottom of the picture where the outside 4" sewer is lowest and (b) keeping the "pit" for the tub trap away from the corner were the 12" x 12" wide footings intersect. Those are not necessarily the best tradeoffs. Some details:
- Black is the footprint of framed 2x4 walls, including the wall finish
- Blue are the bathroom fixtures. I suggest leaving 16" to 17" on either side of the WC, rather than the minimum 15".
- Red is 3" pipe, just the WC drain and the 3" vent through the roof (VTR)
- Green is 1.5" pipe, just the lav trap arm and separate tub vent.
- Orange is the tub drain, which could be 1.5", but as it's under the slab, I think a 2" trap and 2" tub drain would be better.
Negatives of this layout are all related to the tub:
- The orange tub drain runs the long diagonal across the room.
- The orange tub drain is supposed to connect downstream of the WC vent (and lav drain, making the bottom of the 3" vent a wet vent), which could be tricky to have enough space for the fittings. Actually if the tub drain is 2" and the tub vent is increased to 2", it can connect upstream of the 3" vent; the WC is then wet vented by the tub.
- The need for a separate tub vent, which either goes through the roof, or runs around 2+ sides of the room to reconnect to the 3" vent. The latter would not really be too much trouble for a 1.5" vent, and would even be OK for a 2" vent but more annoying.
Possible alternatives:
If principle (b) is not required, then you could flip the tub to have the drain and tub pit near the corner. The shower head is normally above the drain, and it would be nicer to have it on the unobstructed side of the tub rather than by the lav, so that would be a negative. But now the tub drain run is a bit more direct (although it might still jog away from the right wall to avoid the thickened slab edge, then jog back at the WC drain location), and it would be easier to reconnect the tub vent to the other vent. Or it may be possible to bring the lav drain into the slab and wet vent the tub, eliminating the separate tub dry vent (like my drawing in post 18).
You could also consider rotating the WC to face the tub, along with flopping the vanity to beon the 5' wall at the bottom of the picture. That makes for a small vanity (unless you also widen the room to more than 5'), but you could probably reduce the length of the room to under 8'. Then your vents could be in the interior wall rather than in the furred out (doubled) exterior wall. The tub would still need a separate vent but it would only have to run through 1.5 walls to get back to the lav vent (although over the door opening).
Anyway, some ideas to chew on, if you like one of the alternatives better, or some other layout (please specify with a dimensioned floor plan, rather than the weird perspective drawing on top of picture I provided), I'm happy to do one more drawing.
Cheers, Wayne
- Black is the footprint of framed 2x4 walls, including the wall finish
- Blue are the bathroom fixtures. I suggest leaving 16" to 17" on either side of the WC, rather than the minimum 15".
- Red is 3" pipe, just the WC drain and the 3" vent through the roof (VTR)
- Green is 1.5" pipe, just the lav trap arm and separate tub vent.
- Orange is the tub drain, which could be 1.5", but as it's under the slab, I think a 2" trap and 2" tub drain would be better.
Negatives of this layout are all related to the tub:
- The orange tub drain runs the long diagonal across the room.
- The orange tub drain is supposed to connect downstream of the WC vent (and lav drain, making the bottom of the 3" vent a wet vent), which could be tricky to have enough space for the fittings. Actually if the tub drain is 2" and the tub vent is increased to 2", it can connect upstream of the 3" vent; the WC is then wet vented by the tub.
- The need for a separate tub vent, which either goes through the roof, or runs around 2+ sides of the room to reconnect to the 3" vent. The latter would not really be too much trouble for a 1.5" vent, and would even be OK for a 2" vent but more annoying.
Possible alternatives:
If principle (b) is not required, then you could flip the tub to have the drain and tub pit near the corner. The shower head is normally above the drain, and it would be nicer to have it on the unobstructed side of the tub rather than by the lav, so that would be a negative. But now the tub drain run is a bit more direct (although it might still jog away from the right wall to avoid the thickened slab edge, then jog back at the WC drain location), and it would be easier to reconnect the tub vent to the other vent. Or it may be possible to bring the lav drain into the slab and wet vent the tub, eliminating the separate tub dry vent (like my drawing in post 18).
You could also consider rotating the WC to face the tub, along with flopping the vanity to beon the 5' wall at the bottom of the picture. That makes for a small vanity (unless you also widen the room to more than 5'), but you could probably reduce the length of the room to under 8'. Then your vents could be in the interior wall rather than in the furred out (doubled) exterior wall. The tub would still need a separate vent but it would only have to run through 1.5 walls to get back to the lav vent (although over the door opening).
Anyway, some ideas to chew on, if you like one of the alternatives better, or some other layout (please specify with a dimensioned floor plan, rather than the weird perspective drawing on top of picture I provided), I'm happy to do one more drawing.
Cheers, Wayne
So you could have done right tub drain but gave left option for 2 reasons? 1 to possibly avoid more concrete removal in 12x12 corner 2. To run separate vent in its own wall thereby not having to connect to WC vent? Or did you offer #2 reason because having the 2 vents is more compliant to code?
wwhitney
In the Trades
Only for reason #1. Right hand tub drain would be simpler for the DWV layout.
Cheers, Wayne
Cheers, Wayne
I am shooting for RH Drain in tub. But right or left are you proposing 2 vents in this system? (like in your picture)
wwhitney
In the Trades
So with a RH tub, all the plumbing is by the right hand wall, and one option is diagrammed below.
Black is the tub trap blockout in the slab, red is 3" and blue is 2". The 3" vertical vent in the wall is also the lav drain, which I show coming in at a 3x3x1-1/2" san-tee denoted by the green circle. The red circle below it is a 3" cleanout. The lav wet vents the tub and then WC. The 3" vent satisfies the roof vent area requirement.
A couple layout notes: The blue line and short red line running up and down the page can be at a distance from the wall that gets away from the 12" thick footing, although depending on the size and location of the tub trap blockout, the blue might need to 45 to the right at the top of the picture to end up in the right place.
Also, the blue line (tub trap arm, from the trap (not shown) to the wye where it joins the 3" lav drain) is limited by the UPC to 5' in length (and to 2" of total fall). So that may affect where you put the 3" vent in the wall; assuming you use a vanity cabinet, it doesn't have to be centered directly behind the lavatory but can be on the left side of the cabinet.
Cheers, Wayne
Black is the tub trap blockout in the slab, red is 3" and blue is 2". The 3" vertical vent in the wall is also the lav drain, which I show coming in at a 3x3x1-1/2" san-tee denoted by the green circle. The red circle below it is a 3" cleanout. The lav wet vents the tub and then WC. The 3" vent satisfies the roof vent area requirement.
A couple layout notes: The blue line and short red line running up and down the page can be at a distance from the wall that gets away from the 12" thick footing, although depending on the size and location of the tub trap blockout, the blue might need to 45 to the right at the top of the picture to end up in the right place.
Also, the blue line (tub trap arm, from the trap (not shown) to the wye where it joins the 3" lav drain) is limited by the UPC to 5' in length (and to 2" of total fall). So that may affect where you put the 3" vent in the wall; assuming you use a vanity cabinet, it doesn't have to be centered directly behind the lavatory but can be on the left side of the cabinet.
Cheers, Wayne
wwhitney
In the Trades
Lastly, if you can't make the tub wet vent work within the 5' distance limit, or if you'd rather have less pipe under the slab and more pipe in the wall, here's another option.
You can use a separate dry vent takeoff for the tub, which can run up in the wall to a height 6" above the lav, and then run horizontally to connect to the 3" lav vent. That opens up the possibility of moving the 3" lav vent to be directly over the 3" WC drain, with the lav-trap arm horizontal in the wall.
See below. Green is 1-1/2" and the green circle is where the lav stubs out of the wall. The lav trap arm (from trap in the cabinet to the 3" vent) is limited to 42" in length and 1-1/2" of fall. The tub drain has to hit the 3" WC drain downstream of the 3" vent/lav drain. If that's too tricky to do with the 3" vent turning up into your inner 2x4 wall, you can have it hit the 3" WC upstream of the 3" vent if you upsize the tub vent from 1-1/2" to 2". That's because by coming in first, the tub drain is now the WC's (wet) vent, and a WC requires a 2" vent.
Cheers, Wayne
You can use a separate dry vent takeoff for the tub, which can run up in the wall to a height 6" above the lav, and then run horizontally to connect to the 3" lav vent. That opens up the possibility of moving the 3" lav vent to be directly over the 3" WC drain, with the lav-trap arm horizontal in the wall.
See below. Green is 1-1/2" and the green circle is where the lav stubs out of the wall. The lav trap arm (from trap in the cabinet to the 3" vent) is limited to 42" in length and 1-1/2" of fall. The tub drain has to hit the 3" WC drain downstream of the 3" vent/lav drain. If that's too tricky to do with the 3" vent turning up into your inner 2x4 wall, you can have it hit the 3" WC upstream of the 3" vent if you upsize the tub vent from 1-1/2" to 2". That's because by coming in first, the tub drain is now the WC's (wet) vent, and a WC requires a 2" vent.
Cheers, Wayne
Both good options thanks for drawing those and the explanations. You last post for alt venting would be great if I were to trench over to that wall. But the post also highlights what I just came across. I was reading over the install guide for tub and something I had overlooked was the overflow on tub - it requires a 6Wx12L trench meaning in our case it would be yet more concrete removal into that thickest corner part to account for that. Given that, it might be better to just forget the tub and do a full tile shower with curb. If doing so, my understanding is the drain could be placed in various locations such that we could choose to place drain more based on what is easiest to plumb under the slab then build shower around that.
I dont know if doing a tile shower pan if your ptrap ends up higher or lower right under the slab. But in the end would be a better feature than a pre made tub.
Or could flip tub on side and move other fixtures down solving any issue with tub drain. But wanting to add a washer on the right might make it somewhat tight. So in this pic 1 is layout we have been discussing, 2 is tub flipped and 3 is same as 1 but with tiled shower offering flex placement of drain.
I dont know if doing a tile shower pan if your ptrap ends up higher or lower right under the slab. But in the end would be a better feature than a pre made tub.
Or could flip tub on side and move other fixtures down solving any issue with tub drain. But wanting to add a washer on the right might make it somewhat tight. So in this pic 1 is layout we have been discussing, 2 is tub flipped and 3 is same as 1 but with tiled shower offering flex placement of drain.
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wwhitney
In the Trades
Sounds like you have the info you need to figure out your design.
With a shower, you want the drain centered. And it would be nice to go with something more square than 32" x 60", say 42" x 48".
If you want a washing machine outside the bath on the right side of the pictures in your last post, you want to include that in the design now. It will need its own dry vent takeoff, and once its drain joins another fixture, that combined drain can no longer be a wet vent. I.e. that would make the last diagram I posted hard to do, unless you upsized the bath vent to 2" and moved where it hits the 3" WC line upstream of the 3" vent, as previously mentioned.
Cheers, Wayne
With a shower, you want the drain centered. And it would be nice to go with something more square than 32" x 60", say 42" x 48".
If you want a washing machine outside the bath on the right side of the pictures in your last post, you want to include that in the design now. It will need its own dry vent takeoff, and once its drain joins another fixture, that combined drain can no longer be a wet vent. I.e. that would make the last diagram I posted hard to do, unless you upsized the bath vent to 2" and moved where it hits the 3" WC line upstream of the 3" vent, as previously mentioned.
Cheers, Wayne
I thought I had mentioned the washer early on but just looked back and I failed to mention that...yeah will have to have the washer. Plumber (the one who vanished) said he would run all washer plumbing in wall and I think he said he'd terminate it into LAV plumbing. He was the one who proposed the current sawcut area you see here. His idea was TUB, WC, LAV, WASHER. Since then we moved the WC to the right was the only modification.
wwhitney
In the Trades
The washer standpipe needs its own dry vent, and the washer drain needs to join downstream of any wet vented bathroom fixtures.
Here's an option for you, only roughly to scale, blue is for the fixtures (including the laundry standpipe, which is just a 2" vertical pipe, see UPC 804.1 for height restrictions and make sure the top is above the minimum height listed in your washer manual). https://up.codes/viewer/montana/upc-2018/chapter/8/indirect-wastes#804.1
Red is 3" and green is 2". The tub trap arm from the tub trap to the wye where it joins the lav drain is limited to 60" in length and 2" of fall, and you need a 2" trap. The lav vent is 2" and can connect back to the 3" vent in the wall at a height at least 6" above all the fixtures' flood rims.
Cheers, Wayne
Here's an option for you, only roughly to scale, blue is for the fixtures (including the laundry standpipe, which is just a 2" vertical pipe, see UPC 804.1 for height restrictions and make sure the top is above the minimum height listed in your washer manual). https://up.codes/viewer/montana/upc-2018/chapter/8/indirect-wastes#804.1
Red is 3" and green is 2". The tub trap arm from the tub trap to the wye where it joins the lav drain is limited to 60" in length and 2" of fall, and you need a 2" trap. The lav vent is 2" and can connect back to the 3" vent in the wall at a height at least 6" above all the fixtures' flood rims.
Cheers, Wayne
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wwhitney
In the Trades
And one more, this avoids having to run the lav drain in the slab. Orange is 1.5". Now the tub has a dry vent and is wet venting the WC. The lav drain/vent is just in the wall.
On the right, here's what's going on where the orange, green and red all intersect: below the slab, the 3" WC/tub drain is exiting to connect to the building sewer outside. Before it exits, there's an upright 3" combo coming up into the new 2x4 wall, for a 3" stack which runs through the roof. Both the 1.5" lav drain and the 2" washer standpipe drain hit the 3" stack, in either order. If the lav drain is on top, that makes a short vertical wet vent between the lav drain and the washer standpipe drain; for the opposite order, there's no wet vent there.
Cheers, Wayne
On the right, here's what's going on where the orange, green and red all intersect: below the slab, the 3" WC/tub drain is exiting to connect to the building sewer outside. Before it exits, there's an upright 3" combo coming up into the new 2x4 wall, for a 3" stack which runs through the roof. Both the 1.5" lav drain and the 2" washer standpipe drain hit the 3" stack, in either order. If the lav drain is on top, that makes a short vertical wet vent between the lav drain and the washer standpipe drain; for the opposite order, there's no wet vent there.
Cheers, Wayne
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