The framing of a basic gable roof is based on a right angle triangle and the various roof framing components fit the triangle.
Roof return framing.
The run or half the building span is the base of the triangle.
Rafters start at the top of the roof and go down to the eaves but not exceeding the exterior walls of the house.
This structure supports all roof sheathing materials such as plywood sheathing underlayment and of course shingles.
Run both boards long and cut in place.
The rise or height of the roof at its peak is the altitude of the triangle.
Finish the eaves framing after ripping the top of the subfascia with a circular saw set to 26 5 degrees i flushed the top ripped edge with the top of the plumb cut on the rafters and screwed the subfascia to the rafter tails.
Return eaves a common roof structure is made of trusses or rafters.