Howdy. I have a 30x40 polebarn with concrete slab already poured. No water or electric at this time.
I want to add a shower, toilet, sink in a corner of the barn. I want to do this without breaking any concrete.
I will build with wood a raised section for the toilet, shower. The main water and septic line
will come through the sheet metal in the same area. I have drawings on how to do this and in theory I can make it work. I need info from some one with real world plumbing experience. Thanks
this is a great site.

I haven't plumbed a pole barn in 25 years. And then it was a packing house in Arcadia Florida. Let me show you how a typical bathroom with a single vent roughs in. The toilet drain will connect to the sewer or septic tank. The lavatory to connect to the toilet drain line and vent to the roof. The shower to connect to the lavatory drain line and be wet vented by it as will the toilet. Simple huh? Is this what you wanted? Let me know if there's anything more. Good luck, Tom

great thanks. I was afraid someone would tell me "cant be done".

How high will my raised platform need to be. I was planning to use 2x6 then 1" thick plywood for the base of toilet shower. In your opinion will this give me the clearence for the toilet drain pipe to curve out so it can mate with the septic pipe outside the barn. Thanks a lot I really appreciate the info.

I'd raise it a foot or so. You're going to have a 4" closet bend and a 2" "P" trap to put down. You also need to figure a 1/4" to the foot pitch depending on how far it will run to connect to the sewer. More questions? I'm as close as a click. Tom