Simple Under Slab Layout

[Ozark Kevin]

I am building a simple shop that will have a loft "living" area. The loft will have a standard bathroom and a small kitchen. There will be no plumbing fixtures on the main floor, but the sewer drain will be through a concrete slab. This is a small project in a remote area, so no plumbers have been eager to take the rough in job. A license is not required for this type of structure in this county, so I will do this myself. I believe all I need under the slab is shown in the attached diagram. Does this look correct? Thanks.

 

[Tuttles Revenge]

You don't need to take 4" up to the bathroom. 3" is adequate and a lot easier to work with. The bathroom group should also vent through the roof.

Each fixture needs a trap and each trap needs a vent. If you can accomplish horizontal wet venting then you can use the drain of the bathroom fixtures to combine all their vents together. If not then each would have an individual vent that can combine to each other fixtures vents above the flood level of the highest fixture. Then those combined vents through the roof.