Why aren't valley rafters designed as beams regardless of pitch?

[Ron247]

In IRC 2015, it states valleys must be designed as beams if the pitch is less than 3:12. I have always designed them as beams regardless of pitch. Am I being too conservative? I see why a ridge board and a hip rafter that has rafters that set on a wall may not need to be designed as a beam but it also seems to me that if the hip supports rafters that also run to a valley, they too would need to be designed as a beam regardless of pitch.

 

[r13]

I am with you. But don't know how others do.

 

[Ron247]

I know you can omit a ridge board and tie the rafters to each other like they did years ago and the roof is still stable. I do not see how you can omit a valley and not have a failure. I may see how a hip could survive with a non-beam hip rafter as long as the hip kept the rafters from moving laterally.

 

[r13]

Can this be a case that no valley beam is provided.

 

[Ron247]

r13, good point. That would be a case where no valley rafter is needed but 1/2 the rafters are serving the purpose since they are not valley jacks. They would be common rafters and would have to be able to support the load from the adjoining valley jack. My point is that the load at a valley does not appear or disappear based on the roof pitch.