I can't get a plumber in this high crime area. Believe me I have tried. I worked for a plumber. He got the work. I did it. If I know what to do I can get it passed. Ok,I will forget wet venting. I just came back from the old house and see that at the elbow where the 4" soil pipe drops to the basement there is a 2" galvanized vent to the roof. The total length of the soil pipe before the vent is about 5' max. The old lav was 's' traped to the floor and joined with the tub to drain into the 3/2/3/pvc tee which is between the wc and soil pipe.
If I run the 3" drain to the soil pipe in this order--wc, lav, tub--will that soil pipe vent be upc or should I 'p' trap the lav and run a lav vent to the roof. I know 's' trap is not code and I have to 'p' trap the lav. I am not trying to get away with anything. I want to get it right. Thanks for your quick response already.