We started preparing the rafters for our roof whilst the roof plate was at ground level. This is so we aren’t spending to long working at height which presents more dangers.
We offer up our first rafters either side of the ridge beam (our pitched roof varies on each side). This allows us to work out the plum cut (where the rafter meets the ridge beam) and the birds mouth cut (where the bottom of our rafter meets the roof plate, this is notched out around a wall plate). The birds mouth stabilises the rafters horizontal load, and prevents the roof from slumping over time. Imagine a house of cards, where they want to collapse in on them selves, this is not desirable in something you want to live in!
Once we have worked out the cuts of our rafters either side we can make a template, and cut all our rafters at ground level ready for them to go in.