I am adding an ensuite bathroom to the first floor of my bungalow(see floor plan & visio-ensuite.pdf(blue lines are the vents) for pipe diagram). The main stack is 15' away. To avoid loss of headroom in the basement, I want to run a 3" line next to the existing duct work (which is below the joists) to the main stack, and then run the required waste lines between the joists.
After reading the forums I'm still not clear how to vent a WC under this scenario because the 3" line to the WC never goes underneath a wall. Most of what I have read indicates a vent must be vertical(although I'm having a hard time believing how this could be possible in basement(under concrete) scenarios). The only thing I can think of is to 'roll' a 3"x2" wye on its back up 45 deg from the horizontal and tie into the drain of the 2 sinks. Is this legal? Can someone describe the fittings to use for 'C' and 'D' in the attached pdf.
A second question: my 3" to the main stack is below the joists(running perpendicular to the joists) along the main house beam. What is the ideal connection to connect this to:
1. the perpendicular running 3" in the joists. 'B' in the attached pdf
2. the perpendicular running 2" (to the shower) in the joists 'A' in the attached pdf
as both are essentially one pipe diameter higher than the 3" to the main stack
I see a myriad of possibilities:
i) run a wye on its back with a 45 on top, then run a 90 on top turned towards the joists
ii) run a wye on its side then two 45's(cant run a 90 from vert to horiz here) turned up then run a 90 on top turned towards the joists
iii) run some sort of rolled wye at 45 deg turned up from its back then run 2 45s to point toward the the joists
ii) is the least desirable because it takes the most horizontal room and forces my bulkhead in my basement to be wider
Are all 3 legal? It seems from a 'clean perspective' ii) is best because the poop would not go up hill in the other section of the wye, but i) would have the possibility the poop would fall directly down in the wye and sit there, until my shower comes along and cleans it.
I think what I am doing is the same as the attached 'wet vent example' but I cant tell from the example if the 3" wye from the WC to the 2" is laying on its side or its back. (although I am proposing using a 3x2" wye instead of a 3x3 wye and then a 3x2 reducer as shown in the example)
Is my attached diagram(visio-ensuite.pdf) with my wet vent scenario correct?