Timber Frame Joinery & Design Woorkbook on page 46 bottom right corner "In other words,the
thrust in our 12:12 pitch roof is one half the gravity load.

Go to page 62, diagram 4, left frame, we have gravity load of 6000 lbs. and a thrust load of 6000 lbs. Numbers are not proportional.

Obviously we have a mathematical error in one of these diagrams. Which diagram should be used for calculations?

Duane:

I think what's going on here is that on page 46, Ed is talking about the entire roof load, half of which goes to each post.

In Steve's article on page 62, if you add up the load for the entire roof: 1500+3000+3000+3000+1500 = 12000. Again, half of that (6000) goes to each post.