text:  You're not going to know what's going on maybe up in the roof areas until you start stripping it down and you see what others have done before you there. The builder may not even know either or the person building this, but they will figure it out as it crosses their path. That's what builders do. They've got the plans which give them the general rule, but a lot of times based on experience, they just have to figure out, oh, I'm going to put another...