I have a (hopefully) quick question that I haven't been able to find a straight answer on..
When I put drain pipe in for a lav, code (UPC 2009) requires 1 1/4 in. I've heard you can go up one "nominal" size (so I think that would imply going to 1 1/2 in.). What if you want to grow to 2" or even 3", is there code preventing this? Without getting into if it's really a good idea or not, I'm just wondering if it would pass inspection.