Above is sketch of dormer roof framing
to left is the framed dormer
Note bottom of rafters is a compound mitre cut
using a level cut and roof pitch cut
The shingle is attached to flashing with mastic and when the sun heats
the self sealing shingle it will adhere to metal
flashing and prevent water from running under roofing
each shingle comes to the edge of the underlaying shingle ,, gives a
nice clean look to the valley