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VALLEY RAFTER EXAMPLE 
(INCREASING LOAD FROM ZERO TO A MAXIMUM)

    Valley members supporting rafters are sized as beams with an increasing load from zero to a maximum. The amount of load carried by the valley depends upon the how the surrounding roof is is framed.

    Valley Loads are totaled similarly to hip rafters, however care must be taken when determining whether the supported rafters are contributing all or only half of their load to the valley beam. The example above shows both of the possible conditions. The ridge beam on the left might be representative of a cathedral ceiling and the top, non-structural ridge might be rafters meeting at a 1x6 ridge board and typical ceiling joists below supporting a flat ceiling.
    The load to the Ridge Beam shown above is an increasing load from the rafters on the valley side plus a typical uniform load from the rafters on the opposite side (1/2 the rafter span from the ridge to the outside wall). The location of the ridge beam's supporting posts would, of course, dictate whether the increasing load was uniformly increasing over the entire span or just a portion of it.