An architect told me I could place an attic bathroom just about anywhere?

Question

He said by elevating the shower and drain, and the toilet, there would be enough pitch to flow to the location of the drain.

Another contractor told me I must place the plumbing directly under the 1st floor plumbing. Which is correct? How much pitch do I need? How elevated would I need to be to traverse about 15 feet away?

Answer 1

Sunray, the main Q. is "Do ya have to cut thru those rough sawn oak joists to run the drain pipe, or can it just lie inside one to reach the plumbing (drain and vent pipe for toilet)? Money is no object and you are willing to lower the ceiling below the drain and vent pipe for proper pitch. Otherwise put it right above existing plumbling or be ready to run the pipes down another wall and tear out existing plaster and cutting thru those old oak joists to tie the drain into your existing sewage system in the basement

Answer 2

the code minimum is 1/4" rise for every 12", so if yuor main line is 15' away, you need to change your elevation by 3.75".  This can be easily accomplished in the joist space (usually 11-7/8").  Your main concern should be whether the floor structure will be able to support the space in the attic.  Another thing to look at is HVAC requirements if you're in a hot climate, insulation and exiting requirements.