I have spent probably 6-8 hours reading through this forum and other sites in an effort to figure out the correct way to run the waste lines for a bathroom remodel. Hopefully, someone here can tell me if I have it right or not!
Basically, I need to drain a new shower into an existing toilet waste. The toilet waste is 3" and then changes to a 2" vent running up to the roof. My first thought was to simply run a 2" drain for the shower into the 2" toilet vent, which is located above the toilet connection. It seems though that the correct way to do it might be to connect the shower drain below the spot where the toilet connects. I have attached two rough drawings. They are not to scale and do not show the fittings...I'm just trying to get an idea of how to do the layout. I appreciate any help!