wwhitney
In the Trades
0) I think there's some benefit (or a requirement?) to having a 3" cleanout. The lav drain below the floor can be rodded from the trap adapter at the lav (assuming it's not hidden behind a pedestal sink), but I understand having a bigger access is useful for the 3" drains.
So for a possible alternative (assuming it's free and clear under the building), see below. Red is 3" and blue is 2". I'm just showing the horizontal pipes in the one plane. At the upstream end of the 3", it could turn up to a cleanout very low in the wall below the vanity trap adapter. Or a wye could go in below the floor for a cleanout, with the lav drain reducing to 2" upstream of that wye.
I tried to draw it properly in your rendering, with the line at a 45 to your primary axes. So if I did that accurately (low confidence), I didn't quite end up over your vertical, in which case you could use a quarter bend to go 45 degrees off plumb to get over the vertical, then a 45 to go vertical. Or there's no real reason that the horizontal branch drain has to be at 45 degrees, you can just pick a line for the branch drain that goes from the vertical target towards the lavatory and between the shower and WC. Then you just put the wyes for the WC and shower wherever they line up.
1) As to a 45 in the WC trap arm, that's fine to do. No experience on whether it increases the likelihood of clogs.
2) Yes, it's from the trap to the wye where the trap arm hits the wet vent (branch drain).
Cheers,
Wayne
So for a possible alternative (assuming it's free and clear under the building), see below. Red is 3" and blue is 2". I'm just showing the horizontal pipes in the one plane. At the upstream end of the 3", it could turn up to a cleanout very low in the wall below the vanity trap adapter. Or a wye could go in below the floor for a cleanout, with the lav drain reducing to 2" upstream of that wye.
I tried to draw it properly in your rendering, with the line at a 45 to your primary axes. So if I did that accurately (low confidence), I didn't quite end up over your vertical, in which case you could use a quarter bend to go 45 degrees off plumb to get over the vertical, then a 45 to go vertical. Or there's no real reason that the horizontal branch drain has to be at 45 degrees, you can just pick a line for the branch drain that goes from the vertical target towards the lavatory and between the shower and WC. Then you just put the wyes for the WC and shower wherever they line up.
1) As to a 45 in the WC trap arm, that's fine to do. No experience on whether it increases the likelihood of clogs.
2) Yes, it's from the trap to the wye where the trap arm hits the wet vent (branch drain).
Cheers,
Wayne