One of the big changes I’ve seen in my 37 years in the construction business pertains to roof framing. When I started out learning the carpentry trade we framed most of our roofs by hand. This involved getting the proper quantity and sizes of lumber delivered to the job site, then setting up a sawing station. We laid out the rafters needed on the lumber and cut the ridge cuts, tail cuts and ‘bird mouth’ cuts. We cut common rafters, hip rafters, jack rafters, ridge rafters and everything else that was needed to frame a complete roof.
Today most roofs are constructed using trusses. Trusses are engineered specifically for each particular job. Trusses are able to use far less lumber than a traditional hand framed roof. This is because the angled webs with attached metal stress plates distribute the roof load properly over the entire truss rafter. Another advantage to trusses is that they can be erected quickly. I stopped out at the garage we are building for a client. When I got there the carpenters were just getting set up to place the trusses. I stayed and helped them and within 20 minutes all the roof trusses were set. If the garage roof was hand framed it would have taken several more hours to set the rafters and collar ties in place.