I would like to add a 1st. floor full bathroom. We have a powder room on the 1st floor, but need a full bath for my elderly mother. The location of this new bath is almost right below a full bath on the second floor. The soil stack from the second floor bath ties into the waste drain (3" PVC) approximately 8ft. from where the new toilet would be located. We will also have a shower stall and a vanity sink as well. My question is does this new bath installation need a new vent run, or would the soil stack from the second floor serve as the vent?
Thanks
Thanks