vent and drain questions
This is a remodel of a bathroom addition that was built on a patio in California. Questions are what size vent is required for the toilet, sink, and shower. The vanity will have a double sink. Can these vents be combined and if so does it change the diameter? The wet wall of this bathroom backs a drywall of another bathroom. The other bathroom has 3 vents ( I don't know why ). Could I tie the shower and toilet of the new bathroom into the 2" toilet vent of the other bath and the double vanity into the 2" vent for the double vanity in the other bath? The existing drains drop at about a 45 degree angle for about 3' to tie into the 3" main line. Is this acceptable for the toilet? Also all drains currently run off a 3" branch drain of the 3" main line. Should each drain tie in separately or is this branch line method acceptable?