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Tributary Area vs Roof Slope

adamflyer's picture

Tributary Area vs Roof Slope (post #215242)

Hi All,

I am looking at sizing a glulam for a ridge beam on a roof.

For snow load I had thought I had read somewhere in IRC that up to a certain roof pitch you just use the horizontal area but for higher roof pitched there is a correction factor. I have been searching but have not been ablet to find anything. Maybe I am remembering things that are not there... Does anyone know if this is called out in IRC 2012 or any other design practives that related to this?

For dead load it seems it is a simple geometry problem to calculate the weight of actual roof area (instead of the horizontal projected area).

For live load do you use the horizontal projected area or actual roof area?