I am remodeling a bathroom and am re-routing some drain lines. I have a single story home with a crawl space beneath. The drain from the old shower ran between two floor joists. Where I have the new shower the drain line will have to cross 3 joists...My question, is it ok to run the drain line under the joists, or is it better to drill holes. If I run it below the joists I can use one piece of pipe. If I drill through the joists I have to use couplings, and offset the holes to get the 1/8" per foot drop for grade. The new shower will have a 2" drain vs 1.5 from the old shower. I also plan on tying into the former vent. I've attached a picture to help explain. The drawing only shows two joist, I didn't want to redo the drawing.