Well, I forget the during pictures, but this photo is a good one to explain what we did.

The original roof framing is 2 x 6's on 24 inch centers and the span is over 17 feet. Needless to say the barn roof was also a little sway back. We decided to add 2 x 8's originally to every other rafter, or 4 feet on center for the 2 x 10's (when we went shopping for 18 foot long 2 x 8's we realized that the 18 foot long 2 x 10's were only $1.50 more each, so why not install the extra lumber.)

So, we cut and added a 2 x 10 to every other rafter. Getting these in place was a 2 man job with three ladders. We actually had to cut them short and then once we had the new rafter in position we jacked the end at the plate up and added a 2 x 4 under the new rafter to hold it up. We also extended the 2 x 4 out to the edge of the 2 x 10, hoping to prevent splitting in the future and also to transfer the load back to the 6 x 6 plate.