Francis..... I did understand that the photo in your OP was not from your actual job, but rather an approx. look-alike. I do need to see the real plans to start to comment meaningfully, rather than in generalities, I won’t normally do engineering over the phone or on a forum. With either you or a contractor, once we have worked together for awhile, so I know what you know, I know the quality of your workmanship, and know how you interpret what I tell you to do, by my struct. plans and details, a quick sketch or verbally, then I may do some quick engineering by phone to keep you working, but I will still want a follow up hard copy of what you are doing, for the file and so I know you understood. There’s no other way for us to run our respective businesses these days, and to stay on the straight and narrow. I believe I said, or meant to say, the left sketch you posted, a std. symmetrical gable dormer can usually get buy with a ridge board, as long as the rafters line up and there are ceiling jst. ties. And, the R/H sketch, a shed dormer does need a beam, a header up, near the main roof ridge to pick up the shed rafters, which at that low slope ack like simple beams or fl. jsts.
Regarding ‘headers for non-load bearing walls’.... headers, are headers, are beams, whatever you call them. I need to know the span length and loading to design a beam; and then I am concerned about bending and shear stresses, proper beam bracing, reactions and supports below, and deflection for serviceability. You’ve got to develop an eye for the loads and load paths. Most header tables assume generally uniform loads from above, if you call cripple studs and the fl. or roof above as a uniform load, not completely unreasonable in my world. What you need to look for is that the jambs from openings above all line up vertically so one of them doesn’t put a large concentrated load at the middle of a header below. On gable ends, smaller headers often can be used, but most carpenters tend not to do that out of expediency; they have one guy making up headers, jack studs and cutting cripples by the hundreds, and they don’t want to fart around with different depth headers, or don’t have the smaller 2x’s on the job. But, on lightly loaded headers they could use a single 2x8 or 2x10 instead of double 2x’s. But, this presents a problem for them too, since now they need some different sized ripped blocking for sht.rk. or siding nailing at the header. If headers is your new question, lets broach that in a new thread. Ten years of experience provides a whole bunch of “better judgement,” so keep at it.
Building is no longer black and white, and you young code inspectors have a hell of a lot to learn about the practical nature of the process; and then you have the cook book, we call it a code, to memorize, letter for letter, without a good basic understanding of where the letters really came from, or a good understanding of the general structural concepts. This is not to damn you, it is to damn the excessive complexity that is showing up in our codes today. You must understand the basics, because there is no way we can possibly write a cook book to cover everything, all the time. But, that is what they seem to be trying to do. Half the time we are arguing on these forums about how much is a pinch of salt, but nobody knows what the hell we are really cooking. These considerations are what make older engineers who’ve actually designed bldgs. such good plan checkers and older builders such good inspectors, that experience and basic knowledge; otherwise we’re all kinda in the same boat trying to interpret the complexity of the latest codes.
Jobsaver.... I don’t compete with you guys, most of my bldg. inspecting is after the fact, after the problems have developed, and now how to fix them or who’s at fault and gets to pay to fix them. Knock wood, I’ve never had to defend any of my own work anywhere near a court. I think you do have the right idea, we are paying you to keep it safe and done correctly, and to use your experience and judgement, and knowledge of the code, to be as helpful as you can while enforcing the bldg. code in a pleasant way when that is possible and practical. Sometimes you do have to be a dink to get your point across, but that or playing God should not be your general rule. You should offer solutions, within the code and your experience, why not, why make life miserable for everyone; you should not be doing much real engineering if you aren’t one; but you do have one advantage as you suggest, and that’s the difference btwn. my “legal responsibility” and your “advice.” It really boils down to the fact that none of us should be giving advice if we are not qualified in that area. You should get to know a good Structural Engineer, they can really be your best friend, when you’re not fightin with them.