Yesterday while I was putting Woodworks software through its paces, I compared their shearwall values to the ones calculated by the wind load calculator (envelope procedure). The lateral loads compared exactly with no overhangs present. However, when I updated the model in Woodworks and in my calculator to include overhangs there was a slight difference. I spent almost 4 hours trying to determine the discrepancy. My conclusion is that the only difference is the windward overhang pressure is being calculated slightly different than the method I am using. The difference is not huge (10%) but noticeable. I have not been able to determine the method Woodworks software is using to calculate the lateral load imposed by the windward overhang pressure (underside of overhang, positive pressure). I attempted to contact their help desk however their web based form in not functioning and I can't seem to find an email anywhere on their site.
A confused student is a good student.