Hello all:
Great topic, and might I add some comments:
In the older barns the rafter were supported on their centres by a purlin plate. Each rafter was pinned to this plate, and the purlin plates were fastened to each other by a tie beam at each bent. This would eliminate any outward thrust of the rafters to the main plates. These structures stood up well without any signs of stress to the sides of the building until after the early 20th century, at which time due to the advent of hay moving forks and tracks installed into the peaks of most barns, the farmers simply cut off these tie beams to facilitate the movement of hay. It was a very bad move because the wall then began to move outward leading to wall failure.
The analogy of this is in my opinion adding a purlin plate and their tie beams and fastening the rafters well will eliminate in my opinion any stress on the outside wall main plates--check it out!!
NH
