I'm building an addition onto a home myself. It started as a 2,400 square foot total renovation / addition. Due to a change here and there, it has become a 4,200 square foot renovation / addition! I am having to do everything myself to keep costs low in order to even complete the project. Needless to say, I have to work into the wee hours of the night because I have a full time day job as well.
The home has 4 1/2 baths, a full kitchen, a second kitchenette, a laundry room and sinks in the basement and garage. It also has a wet bar area in another two areas.
I am trying to vent every single fixture as well as have the main drain stacks vented. All the vents will tie together in the attic. The sink vents are clear in all the diagrams I've seen however I'm held up because all the plumbing books I read mention that the vent line cannot run horizontal until at least 6" above the flood line of the fixture it is venting, which i'm not sure about when it comes to toilets and bath tubs.
I'm probably being over causious with my vents by adding too many, however I would rather be safe than sorry. My plan for the bath tubs and toilets is to add a vent pipe within the floor joints below the toilet and tubs, about 6" to 12" from the trap of the tub and about the same from the toilet 90 fitting each with a sanitary Y fitting . I want to then run the vent paralell to the drain pipe within the floor joists ane run it back up the wall behind the toilet and also near the tubs in the tub scenario and then run it up to the attic.
My confusion is that no diagrams ever show tubs or toilets vented individually, only through the main stack. I understand the concepts of x amount of feet from the main stack is okay to have something wet vented, etc, however like I said I want to be extra safe.
My question: Is there any code restriction against having a vent in the drain line beneath a toilet or tub running parralell to the drain line under the fixture and then up a wall? I would make certian the vent line intersects with the drain line at least 45 degrees or less from the top of the drain pipe, as the books state. I also understand you have to be a certain amount of distance away from the trap with the vent line tie in so you don't siphon water out of the trap when the line is draining.
I really appreciate any advice. Thanks a lot.