I need your input on holes that were drilled by a plumber when my home was built. I have 2 x10 joist. The holes are 2 1/2" for a 2" drain pipe. I always thought you had to stay 2" from the top and bottom so as not to compromise the integrity of the joist. It bothered me that he could have just went through 1 to enter into the cabinet but he drilled through 2 separate joist. I have granite countertops on the cabinets above. How concerned should I be and is this a code violation? Thanks for your input and thought on this.