Hello. thanks in advance for the help.

I am updating a second floor bath and had question about toilet venting. The existing toilet has no vent and runs a 3" 8' horiz DWS into a 3" stack to the basement, then 8' horiz run over to the main house cast stack via 3x3x3 wye.

I hired a retired master plumber to do the work but he has a problem now and cant get to the work. He gave me the layout, detailed instructions, parts list and plenty of material.

My question is about venting. The space I am working is is very limited and his design calls for a 180 degree change in direction of the soil by way of two street 90's back to back.

I read about using a 3X2X3 wye downstream of the closet flange, installed on its back and turned up 45 degrees then a street 45 and then turned up into the wall via a 90, then out to a 3" and through the roof.

Here are pics of the two set ups I am considering. The 180 is the master plumber design and other is mine. (The venting is 2" and will extend through roof for both setups) I layed them out quickly but the general layout is evident.


Thanks in advance for the help. I can't get a hold of my plumber for a week or more..