Heavy rafter sizing

[Ljohnsaw]

Trying to use @Don P toolbox to recheck my rafters but don't know what one to use. I see the 2"-4" 'beam' and tried that but also not sure on the lengths to use. Snow load is 350 psf ground and, IIRC, about 240-250 on the metal ventilated roof, 53° pitch. 

Pine rafters span over three beams. Ridge, mid and wall. Horizontally, they are 6' apart. On the angle, 10'. They will be sheeted with 2x8 T&G pine. Rafter spacing is 24". My model has 4x7 and the engineer reviewed the model. However, on my approved plans, I noted in one spot that they are 5x7. 

[Don P]

I'm unclear, which pine and what is the actual rafter size?

Use the horizontal measure for rafter span... technically live load is horizontal projection and dead load is actual length.

Then, the simple beam calcs are for, simply supported beams, that is beams resting on a PAIR of supports. You have a continuous beam over multiple supports... I think I put a calc in there. Basically, most of the time the major difference is the reactions, the center support takes 5/8 of the load and the ends split the remaining 3/8.

[Ljohnsaw]

Sorry, Don. Ponderosa pine but they just call it pine out here. The loggers get miffed when I ask if that's ponderosa.

Right after I posted this, I sent a message to my engineer at Fire Tower. Within 30 minutes Duncan replied that I'm all good with the 4x7 rafters.

Fire Tower is awesome! 👍 

I drafted a follow up post to this thread but it didn't post and I didn't check.