So a vertical support at this point is needed. Where the hip roof is attached to the main roof at the ridge board both valley rafters and the hip roof ridge board transfer approximately 2400 lbs. The user enters the member geometry, adds loads, holes and other relevant data and then selects a product for analysis. It is simple to use, yet flexible enough to analyze a variety of common applications. However there is typically no load bearing wall under the hip valley rafter needed for support. BC Calc performs engineering analysis to help our customers size beams, joists, columns, studs and tall walls for their building projects. In general the hip valley rafter needs to be one to two sizes larger than the jack rafters, if you can add a few support braces. The jack rafters were pulling away from the hip valley rafter due to the excessive deflection. Engineered Wood Products Australia // Plywood Webs. For further information on LVL go to Figure 6: Branding for LVL products. I have added pictures of Friday’s inspection where the 2圆 hip valley rafter had about a 4" deflection mid-span. In the span tables in this manual, LVL must attain a Modulus of Elasticity of 10 MPa. Total deflection was 73% of the maximum allowable by code for the single LVL and 65% for the double LVL beam. The two 2x12s failed 220% in bending and 6% in deflection.To make the hip valley rafter a clear span beam it needed to be one LVL beam 1-3/4" x 11-1/4", 2.0E, 2950Fb or two LVL beams 3-1/2" x 9-1/4". LVL is stronger than standard timber which gives you a floor or roof with less deflection, that extra span, or the perfect lintel/beam solution. The roof structure is assumed to span from. The listed span is the clear distance from face to face of supports.The design is based on a simple span for the unfactored roof loads shown in the table. The table indicates the number of 13/ 4' wide LVL plies to be used for the given application. The hip valley rafter failed in all combinations including two 2x12s, which was modeled without intermediate supports. Width of Building Beam Span Support Notes: 1. By adding a mid-span support the 2圆 common rafter passes. Based on the loading the common rafter without intermediate bracing fails in bending and deflection. The loading is based on a shingle roof, 1/2" plywood on #2 D.Fir-L 2圆 rafters. I did the calculations and the common rafter carries 7.42#/linear foot deal load (DL) and 20.48#/linear foot snow load (SL). Just by visual observation you can see the hip valley rafter carries significantly more load than the common rafter. The yellow shaded areas show the area loading that is transferred to the common rafter and the hip valley rafter. The hip valley rafter is 22’-8" long with the attached jack rafters at 16" on center. In this graphic the common rafters are 17 feet long spaced at 16" on center. Most of the time the hip valley rafter is the same size as the common rafter. LVL beams commonly are available in widths of 1-3/4, 3-1/2, 5-1/4, and 7. I have attached a graphic showing the loading on a common rafter and a hip valley rafter.
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