I'm working through my first 2009 daylighting calculations using the Prescriptive Method. It seems that in 2.2 we used net square feet of the rooms. Now the 2009 template and Supplemental Calcuation spreadsheet call for gross area. First of all, what do they mean by gross area vs. net? I assume the net area would be the interior wall to wall area of the room. What area would be added to this for gross area?