I recently had to frame a roof with a snub hip layover valley. Normally I would frame broken hips from ridge to ridge, but in this case the engineer wanted each roof fully sheathed. This is maybe the 3rd time in 20+ years I’ve had to do this. Here is how I figured the angles (they worked, but I’m not 100% sure I’m doing this right, though the angles fit and everything planed out).
First off, while I know the trig to figure the angles, I don’t bother. Instead I use the BuildCalc (available for IOS and Android) app on my smartphone. Here are a few basics to get us started. The upper ridge of the roof is a 6-12, and the lower roof is a 7-12. I enter the information in that order. The 6-12 is the MAJOR roof and the 7-12 is the MINOR roof. This is important so we can keep track of which angle in BuildCalc corresponds to the right roof.
