Toby Bonilla installs 2x6 sisters to the existing 2x4 rafters.
To optimize headroom, the engineer allowed the crew to cut a slight taper on the underside of the sisters from the point where the rafter ties intersect to the end near the wall plates.
The rafter ties are fastened to the rafters with structural screws.
Note the eye hook attached to the top plate of the wall to secure the come-along. On every other rafter assembly, the crew also installed 2x4 collar ties just below the ridge board.
When the job was completed, the sag in the ridge and the bow in the outer wall were vastly improved.