Maybe, but I did do the math on it. I have a calculator that I downloaded from the web that is used for simple beam calculations. I used a combined load of 50 psf and the wood specs from the lowest grade of E.W.pine.(The roof is 16x25 with 8:12 pitch)
The plates are 8x14x24' sitting on posts 1 ft from the ends.
It would have been easier to plane if they were only 12" instead of 14". Anyway it's done and the client loves it.
Thane